Return stats – Heavy Topspin

What Does Felix Auger-Aliassime Do So Right On Indoor Hard Courts?

Felix Auger-Aliassime has earned a reputation as a world-beater on indoor hard courts. He’s no Jannik Sinner–as Sinner reminded him all four times they met last year, twice indoors–but FAA is a fearsome customer against just about anybody else.

Last week the Canadian added to his indoor title haul with his second-straight championship in Montpellier. This time, he straight-setted Adrian Mannarino. While that win doesn’t particularly raise any eyebrows, the body of work keeps growing. It’s his eighth career title indoors, three of them at ATP 500s. Last fall in Paris, he also reached his second Masters final. (The first was in Madrid, the indoorsiest of the clay Masters.)

What’s the secret?

The conventional wisdom is that he has a big game, especially a deadly first serve. The controlled environment indoors, plus typically fast conditions, play to his strengths. The serves skid across the court even faster. His weaknesses are mitigated because the bounce is more predictable and because points are shorter.

All that sounds plausible. My only gripe is, couldn’t you say that about a lot of players? The whole paragraph applies, almost word for word, to Hubert Hurkacz, who has two Masters crowns on outdoor hard, plus a clay title, yet just a pair of indoor 250-level championships. What about Matteo Berrettini? The description might match him even better, yet the Italian has never won a title indoors. He has reached only one indoor 250-level final.

Before we go to the numbers, let me give you my seat-of-the-pants theory. FAA has huge weapons, but he doesn’t always play like it. He doesn’t consistently swat away easy plus-ones like Berrettini does. He gets sucked into long rallies, where he’s often at the disadvantage. Indoors, though, he knows what the tactics are, and he plays the way he should play. Indoor Felix, then, is the best Felix, both because his game is suited to the conditions and because he shows up with the right approach.

On the other hand, the last two points against Mannarino on Sunday were 8- and 18-shot rallies, respectively. So, you know, don’t trust my pants.

Numbers!

You can, however, trust the spreadsheets. The Match Charting Project has well over 100 Auger-Aliassime matches. Going back to 2020, the total includes 41 on indoor hard and 40 on outdoor hard, nicely suited for some comparisons. I was tempted to throw out the seven Tour Finals matches from the indoor tallies, because they skew the quality of the opponents, but the Canadian’s indoor averages are about the same with or without them.

Start with serve stats:

Surface       Unret%  <=3 W%  RiP W%  
Indoor Hard    35.7%   47.7%   55.5%  
Outdoor Hard   32.8%   43.4%   49.7%

About three percentage points more serves don't come back, and there's an even wider gap in points polished off on the serve or plus-one (the "<=3 W%" stat). The biggest gap here is in points won when the return comes back. Sub-50% is below average, especially for hard courts. 55% or better is very good, even in fast conditions.

Almost all of the indoor/outdoor serve differences are thanks to the first serve. FAA's second-serve numbers are about the same regardless of roof status.

Of course, Felix isn't the only guy on tour who wins more easy serve points indoors. I don't have comprehensive stats on the indoor/outdoor split, so I can't tell you the exact tour average. But we can compare how much Auger-Aliassime gains on serve to how much he gives up on return:

Surface        RiP%  RiP W%  
Indoor Hard   65.3%   48.8%  
Outdoor Hard  67.5%   43.2%

He retrieves 2.2 percentage points fewer serves indoors--better than the 2.9-percentage-point difference he gains on serve. But when he gets the serve back, he's actually better indoors than outdoors! He gains five percentage points in that department on serve, and he gains the same margin on return.

This might dovetail with the conventional wisdom. His monster serve really pays off indoors. And predictable conditions give him a bit of cover on return.

Whatever the reason, Auger-Aliassime's groundstrokes are way more effective indoors. My Potency metrics, FHP and BHP, combine winners, unforced errors, and shots that set up winners and errors. They give you one-number estimates of how valuable each shot is, and... wow:

Surface       RallyLen  FHP/100  BHP/100  
Indoor Hard        3.7     +8.5     +0.0  
Outdoor Hard       3.9     +3.2     -5.8

His indoor points are a little shorter, but I assume that is typical. I would've guessed that the difference was greater.

The Potency numbers (expressed here as rates per 100 shots), tell a more emphatic story. A +3.2 FHP/100 is ok, not great. Tommy Paul and Ugo Humbert are in that zone. On the other hand, +8.5 is the 52-week average of Carlos Alcaraz. A -5.8 BHP/100 is near the bottom of the pack, below the likes of Ben Shelton and Grigor Dimitrov. By contrast, +0.0 is, as it sounds, a good solid average.

These numbers don't drill into the "why" questions that naturally follow. But they help us pick between theories. I suspect that much of the difference in groundstroke stats has to do with the shots he gets to hit. The winners are downstream of good serves. Auger-Aliassime picks up some aces, but he picks up more plus-one (or even plus-two) winners, and those make his forehand and backhand numbers look good.

The "indoor predictability" thesis also looks good here. Remember that everybody should benefit from that--and not everybody's numbers improve like Felix's do--but it may be that the Canadian is more-than-typically exposed by the vagaries of outdoor play.

All the angles

Quick thought experiment. Picture Roger Federer hitting an ace.

Now imagine Auger-Aliassime hitting an ace.

What specific serves came to mind? If you're like me, you pictured Federer shooting a bullet right down the tee. And then you visualized FAA hitting a flat bomb out wide.

Of course, both guys hit plenty of aces in every direction. The charting stats suggest that Felix has a slightly better chance of an ace when he goes up the middle. (Federer did too, by a bigger margin, as do most players.) Still, this indoor/outdoor split caught my eye:

Surface       Deuce Wide%  Ad Wide%  BP Wide%  
Indoor Hard         50.5%     47.8%     33.7%  
Outdoor Hard        46.9%     45.2%     41.0%

Each column shows how often Auger-Aliassime opted for a wide serve in various scenarios. The first-serve differences are probably more marked, because his second-serve tendencies are about the same.

Indoor, he goes wide more often--but less often under the pressure of break point. While the margins are rather slim, it seems like the wide serve becomes his bread-and-butter indoors, and he uses the tee serve to mix things up on break point--because he's hitting more wide serves the rest of the time.

Wide serves are more likely to come back, but they don't make the returner any more likely to win the point. Especially against Felix: His signature serve might not even be an ace, but a wide bomb that the returner just barely plops back over the net.

The fact that he hits more wide serves indoors explains a lot. He gets a few more unreturned serves (as everybody does, probably), but he gains more of an advantage on the serves that (weakly, oh so weakly) come back. His groundstroke stats sparkle, padded by those easy balls.

Here's one final comparison:

Surface       2ndAgg  
Indoor Hard       +7  
Outdoor Hard     +46

"2ndAgg" is the Aggression Score stat tailored specifically to second serves. A higher score means more double faults and more unreturned second serves. Lower means fewer risks on second balls. +7 is quite conservative: Only about a dozen players consistently score so low.

But--those careful second servers include Sinner, Hurkacz, and Berrettini. With a game like Auger-Aliassime's, the second serve isn't the time to take risks. And indeed, in all of his indoor finals, he has never topped a double-fault rate of 5%. In the Montpellier final, he missed his second serve just once, and he committed no double faults at all in the quarter- and semi-finals.

Here, finally, is some support of my seat-of-the-pants theory, that when Felix goes indoors, he plays the way he ought to be playing all the time. He stays within himself, which is still imposing enough to earn a lot of cheap points. It's not a particularly complicated story, and I'm still not convinced why it doesn't apply to a half-dozen other guys on tour. Maybe it is all about the wide serve, the signature shot that allows Auger-Aliassime to manage risk and put his opponents on the back foot, all at the same time.

Defanging the Ball Bashers With Sara Bejlek

On Saturday, 20-year Sara Bejlek won her biggest title–by far. She had just slipped out of the top 100, so after qualifying for the main draw in Abu Dhabi, she charged past the likes of Jelena Ostapenko and Clara Tauson, then secured the trophy with a 7-6, 6-1 win over almost-top-tenner Ekaterina Alexandrova.

It’s tough to overstate just how out of the blue this was for the Czech. By ranking, Ostapenko, Tauson, and Alexandrova represent three of her four highest-ranked victories. Her two other main-draw victims, Sonay Kartal and Ashlyn Krueger, also count among her top ten. And she beat Kartal 6-0, 6-2.

That’s a big-hitting set of opponents. Bejlek, by contrast, lacks the power weapons that are becoming standard on the WTA tour. As a left-hander, she practically begs us to call her “crafty.” One upset against that group is plausible enough: After all, Ostapenko’s low-percentage tennis invites chalk-defying outcomes. But so many?

The final

I don’t pretend to be an expert on the Czech’s game. She has only a couple dozen tour-level matches under her belt, so she’s a newcomer for most of us. That said, we now have a detailed match chart from Saturday’s final that offers some clues as to how Bejlek battled the barrage of ball-bashers in ~~Bahrain~~ Abu Dhabi.

The conditions helped. It was windy, and the conditions were slow. None of that favored Alexandrova, who likes predictable balls she can smack flat back across the net. The court speed not only made it difficult for Alexandrova to hit through the court, it gave her a little less pace to work with on Bejlek’s own balls. Surely the Russian must have wished she had played indoors in Ostrava(!!!) instead.

The lefty’s game plan seized on those advantages. She looped balls back down the middle. She sliced more than she had to, refusing to give her opponent a predictable bounce height. She mixed in some almost impossibly slow serves. She won the first point of the match with a dropshot-lob combo that, while she didn’t attempt many more, surely gave Alexandrova pause.

The central result was that the Russian just couldn’t hit winners. By my count, she ended with 13 winners against 37 unforced errors. Just as telling as the abysmal ratio was that the 13 winners represented less than 10% of total points. In her last 60 charted matches–going back to 2022–opponents have held her under 10% just six times. When they do, it’s usually because they take the racket out of her hands by playing hyper-aggressively themselves. Two of the opponents in question were Anisimova and Yastremska.

Bejlek, by contrast, gave Alexandrova ball after ball that looked like it should have been obliterated. In different conditions, or when the Russian was in better form, maybe the winner count would have been much higher. But from the first few games, it was clear that the Russian wasn’t confident in her ability to take control. Big, aggressive hitters usually have more influence on rally length than more passive opponents, but that wasn’t what happened on Saturday. The average point lasted 5.1 strokes, tied for third-longest among the nearly 100 charts we have from Alexandrova’s career.

Translated into tennis cliché: Bejlek let her opponent beat herself.

If we can extract one concrete skill from the Abu Dhabi final, it’s that Bejlek doesn’t let servers overpower her. 85% of Alexandrova’s serves came back, compared to a 52-week average of 75%. Again, we don’t have much data yet on Bejlek, but here’s another bit of evidence: In Madrid two years ago, she retrieved more than 80% of Rybakina’s serves. The Aussie Open champ is the toughest on tour to return, usually holding opponents to around 67%.

Despite all the frustrations and all the extra shots she had to hit, Alexandrova nearly pulled out the first-set tiebreak. She led 4-2 at the change of ends before getting dragged into a series of long rallies broken up only by a couple of well-executed short points from the Czech. Having dropped the 95-point slog that was the first frame, Alexandrova ran out of ideas. She simply watched the error count soar.

You don’t win slams by letting opponents beat themselves–marathon runners notwithstanding. But in the hands of someone persistent enough, it’s a game plan that can keep you in Bejlek’s new neighborhood of the top 40. With 500 points on the books from Abu Dhabi, the left-hander has the rest of the season to prove that she belongs.

Carlos Alcaraz Will Return Your Serve. Good Luck With That.

It often feels fruitless to pick out the strongest aspects of the Carlos Alcaraz game. (Sinner’s, too, of course.) He is so good at everything that we tend to focus on the same few particularly attention-grabbing attributes. The knee-buckling dropshot, the outrageous will to win (and corresponding fifth-set record), the forehands at full stretch.

We don’t ask often enough why Alcaraz or Sinner won a match, because it seems obvious. They’re simply better than everybody else, except for maybe Novak Djokovic or Cameron Norrie on a good day.

And it’s true, there’s no single reason why. (There’s never a single reason for anybody, though most players make it easier to isolate a small number of effective shots or tactics.) All we can do is focus on one part of the Alcaraz game, then goggle at it.

Today, let’s goggle at the return of serve.

Here’s a fun place to start. Djokovic completed five matches at the Australian Open. Take a look at his first-serve win percentages from those five matches:

Opponent           1st W%  
Martinez            93.2%  
Maestrelli          86.0%  
van de Zandschulp   77.0%  
Sinner              71.4%  
Alcaraz             65.9%

Djokovic, at any age, is an outstanding hard-court server. 71.4% is below average: Sinner did a nice job on return, even if he forgot on some break points. 65.9%, though, is unreal. Of the ATP top 50, how many players do you think win fewer than 66% of their first-serve points? One: Sebastian Baez. Alcaraz turned Djokovic into Sebastian Baez.

It wasn’t a fluke, either. Djokovic won 66.1% of first-serve points against Alcaraz in the US Open semi-final last year. Those two aren’t the absolute worst serving performances of Djokovic’s last twelve months–Vacherot held him to 60.5% in Shanghai, and Musetti kept him to 61% in their abbreviated match–but they are close.

Two separate skills

Charting data allows us to break down service returns into two components:

Getting serves back
Winning points after getting the serve back

Pretty straightforward stuff. You want to get as many serves back as possible, but you also want to set yourself up to win points after you do.

There’s something of a tradeoff here. Jaume Munar is a good example of somebody who retrieves a ton of serves but loses a lot of the points because he doesn’t do enough with the return. Andrey Rublev is the opposite, not getting many returns back, but winning a relatively high percentage when he does. Adjusting for surfaces and opponent quality, the end result for Munar and Rublev is about the same, even if they get there via such different routes.

The tradeoffs don’t apply to everyone. Take a look at the scatterplot, which shows percentage of returns in play, and in-play return-points won, for all ATPers with at least ten charted matches in the last 52 weeks. The higher you are above the green regression line, the better. You can mouse over each dot for player details, but I don’t need to tell you whose dots are red:

ATP Returns in Play

10+ charted matches (last 52 weeks) • RiP% vs RiP Win%

Sinner & Alcaraz

Mere Mortals

Regression Line

Both halves of Sincaraz get more returns back than average, and they win more of those in-play points than anybody else.

(How they win the in-play points is itself a multifaceted question. Both Sinner and Alcaraz rank in the top six by my forehand and backhand potency metrics, and Alcaraz’s backhand rating continues to creep upwards. I also dug into their shot tolerance last year and found new statistical categories for them to lead.)

Remember I started out by talking about first-serve returns. That’s where Alcaraz really shines, even above his brother in world domination. Same idea, first-serve returns only:

ATP First-Serve Returns in Play

10+ charted matches (last 52 weeks) • 1st Serve RiP% vs RiP Win%

Sinner & Alcaraz

Mere Mortals

Regression Line

Alcaraz is the right-most red dot. There are 36 players on that plot, and Alcaraz gets more first serves back than all but four of them. (And he’s basically tied with Medvedev, the blue dot underneath his.) There’s no tradeoff for Carlitos: He gets more balls back than almost anybody, and he wins more of those points than anybody except for Arthur Fils (barely), Sinner (barely), and Rublev (whack!).

Both skills were on display in Sunday’s final. Alcaraz put an astonishing 76.5% of Djokovic’s first serves in play–almost off the right side of the scatterplot, against an elite opponent, on a hard court. I say “astonishing,” but was it even a surprise? At the US Open, Alcaraz got 75% of Novak’s first serves back.

When you can handle so many first serves, the win rate barely matters, but of course Carlitos did fine in that department as well, winning 44.6% of those in-play returns in Melbourne. Lower than his usual rate by a healthy margin, but hey, it was still Djokovic, and a massive number of in-play returns is always going to include a fair few weak ones.

When I started looking at returns in play about a decade ago, the tradeoff was clearer. More players fit the Munar or Rublev molds, getting a lot of serves back, or winning a high percentage of points when they did–but not both. Now, the relationship between the two stats is positive, but only slightly. They’re best understood as unrelated.

But for Alcaraz, tennis is built out of a dozen or so unrelated skills–all of which allow him to tower over the field. Sinner is close enough, and his serve might tilt the scale slightly in the other direction. Everybody else, though, is left scratching their collective head. Djokovic became the greatest of his generation by taking away opponents’ second serves. When Alcaraz neutralizes your first, what’s left?

The Rybakina Serves That Tipped the Scale In the Melbourne Final

In Saturday’s Australian Open final, Elena Rybakina won 92 points. Aryna Sabalenka won 92 points. Rybakina won 76% of her first serve points; Sabalenka won 75%. Both players held on to 48% of their seconds. Even their average first serve speeds were nearly identical, Rybakina’s 178 km/h nipping Sabalenka’s 177 km/h.

Only a few moments really mattered. Sabalenka converted two of eight break points. Rybakina converted three of six.

With such narrow margins, we should be cautious to draw conclusions about tactics and player skills. Flip one or two of those break opportunities, and it would have been a very different trophy ceremony. Anybody who tries to tell you “why” Rybakina won should keep that in mind. Still, Sabalenka would surely like to know how to secure another half-dozen points and put the result out of the range of luck. Rybakina will hope to do the same.

Pick target, hit target

Rybakina is the best server in the women’s game. Her ace rate over the last year is better than 10%–a percentage point ahead of second place (Osaka), and miles ahead of Sabalenka’s 6%. Rybakina has won nearly 75% of her first-serve points, while no one else cracks 73% and only a few players are on the north side of 70%.

At key moments on Saturday, Rybakina dazzled with her ad-court serves out wide. She saved the only two break points she faced in the first set with back-to-back unreturned serves, both wide. She finished the match with another signature delivery, acing Sabalenka out wide on match point.

If you’re looking for a “why,” it’s tempting to focus on those wide ad-court serves. Rybakina made 18 first serves when she aimed for that corner, and she won 14 of those points.

But! It’s not the ad-wide corner, specifically. Rybakina was even deadlier when she targeted Sabalenka’s backhand corner in the deuce court. She landed 14 of those first serves, winning 13.

Here’s the Rybakina method for defeating the world number one:

Have a world-class serve
Aim first serves at the backhand corner
Make half of them

Easy, right?

Apparently not easy

Fair enough, most players don’t have anything like Rybakina’s serve. A few–Osaka, Noskova, Qinwen–can do a decent impression on a good day. Still, it’s an uphill battle to knock off Sabalenka with aggression from the line.

What’s striking, though, is that most opponents don’t really try.

Across 120+ charted matches since the beginning of 2024, Sabalenka’s opponents aimed their first serve at her backhand corner about 40% of the time. (That doesn’t mean they aimed 60% at the forehand corner: A fair number of first serves don’t land close to either corner.) In the vast majority of matches, her opponent aimed half or fewer of their first serves at her backhand corner.

On Saturday, Rybakina targeted the backhand corner 63% of the time.

The first serves that landed in were so devastating in part because she took a low-margin approach. Rybakina already misses more first serves than almost anyone on tour: Her 57.4% first-serve-in rate is worse than 45 of the top 50 women. Against Sabalenka, she succeeded exactly half the time when she fired in that direction. Corner-aimed serves are (unsurprisingly) lower-percentage for everybody, but her 50% was even worse than tour average.

It’s a smart tradeoff. Combine the two numbers, and we see that on 32% of her service points, Rybakina put a first serve in play to Sabalenka’s backhand corner. Those, as we’ve seen, are as close to guaranteed points won as you can find. Sure, that leaves 68% of service points to worry about. Yet as much as Rybakina’s premier weapon glitters, she’s a solid average at everything else. She’ll pick up a lot of those other points with quality second serves or rocket-powered firsts to the forehand corner, or by winning baseline rallies.

In the past two years, only a handful of players have managed to put first serves to Sabalenka’s backhand corner on as many as 32% of points. Even then, it doesn’t always work: Marketa Vondrousova, for instance, is unparalleled at hitting her targets, but her deliveries are softballs in comparison. For the players who can serve big, though, Rybakina may have pointed the way to tougher challenges against the world number one.

Ka-zam

This might be a recent refinement to Rybakina’s match tactics. We have over 80 charted matches for her since the beginning of 2024, and she has rarely aimed so many of her serves at the backhand corner. To be clear, she doesn’t need to. She straight-setted Sabalenka for the year-end title in November with only 44% of first serves pointed at that target.

But suggestively, Rybakina hit nearly as many first serves to the backhand corner in her Australian Open quarter-final match against Iga Swiatek. While she wasn’t quite as successful, landing just 40% of those attempts, the end result was encouraging. Even with all the misses, backhand-corner firsts accounted for a quarter of her service points. And she was as eye-poppingly successful on those points against Iga as she was in the final. Swiatek salvaged just 1 of 12.

It remains to be seen whether this is repeatable. When Rybakina is serving at her best, peppering the backhand corner is probably a good way to take advantage. (Unsurprisingly, since this is something tennis coaches tell twelve-year-olds.) If she’s misfiring, low-percentage first serves are probably not the way to fight her way through.

And surely, the world number one will start taking a few more backhand-return reps. She doesn’t have to turn into Andre Agassi to negate Rybakina’s new-found advantage. She just needs to defend that corner a little better. 94 or 95 points would have gotten the job done on Saturday. Even against a world-class serve and superb tactical execution, Sabalenka won 92. The two women will continue jostling for an edge, and it looks like the battle will increasingly take place with Sabalenka leaning to her left.

What Do We Make of Sofia Kenin These Days?

*Sofia Kenin in her run to the Tokyo final last year*

Is Sofia Kenin back? Was she ever gone? Was she ever there in the first place? Has any player so persistently defied categorization?

Big questions aside, Kenin is suddenly more relevant than she has been in at least 18 months. This time last year, she was suffering through a nine-match losing streak. She would add another bad patch in the summer and fall out of the top 150 before reaching last October’s Tokyo final. Since then, she has lost only one first-round match (when she drew Coco Gauff in Melbourne) and made another 500-level final in Charleston. Kenin had set point on Sunday to force Jessica Pegula into a third set before the veteran summoned her mysterious forces and finished the job.

This is all a far cry from 2020, when the American bracketed the pandemic pause by winning the Australian Open and reaching the French final. But her Charleston showing moves her ranking back up to 34, the highest it has been since late 2023. Her Elo rating is even better, good for 25th on tour.

What is working again for Sonya? Is she back in the top 40 to stay?

Oh, those groundstrokes

When the Kenin game is clicking, it is a joy to watch. She is one of the most versatile players on tour, with the ability and willingness to deploy just about every shot in the book. She tried ten drop shots in the Charleston final against Pegula and sent both forehand and backhand slices across the net. I’ve even seen her win points with moonballs.

In the 2020s WTA, though, versatility can only be the icing, not the cake. Fortunately for the 26-year-old, both her forehand and backhand are among the game’s best. By my Forehand Potency (FHP) metric, she ranks 16th on tour over the last 52 weeks, in between the fearsome weapons of Iga Swiatek and Amanda Anisimova. Her backhand is the signature shot, and it rates even better, coming in 9th.

Combined, she gets more value from her groundstrokes than almost anyone else. Here is the top ten, based on charted matches since this time last year:

Player                 FHP/100  BHP/100  Combined  
Jelena Ostapenko          18.7     11.0      29.7  
Amanda Anisimova           9.2     14.1      23.3  
Aryna Sabalenka           13.0      9.3      22.3  
Ekaterina Alexandrova     13.6      8.5      22.1  
Danielle Collins          12.7      9.0      21.7  
Linda Noskova             14.1      7.4      21.5  
Iga Swiatek               10.0      9.0      19.0  
Madison Keys              11.3      7.5      18.8  
Sofia Kenin                9.4      7.8      17.2  
Jessica Pegula             8.3      8.0      16.3

For all the heavy hitters on that list, Kenin is more like Pegula than the rest. She attempts to dictate with placement, not power. Give her an opening, and she’ll rarely squander it. She’ll miss as much as some of these sluggers, but that’s because she relentlessly aims for the lines. The overall tally tilts in her favor.

She falters when she doesn’t have enough space to work with. Pegula, boasting perhaps the best anticipation of anyone on tour, consistently cut down the angles Kenin had to work with on Sunday. Sonya doesn’t have the patience to wait for the next opportunity, so she aimed for narrower and narrower spaces. The result, predictably, was a giant pile of unforced errors. She committed 33 of them off the ground–nearly one in four points.

Speaking of patience: That’s one category where she resembles the power hitters on that last list. Her average point in the past year has averaged just 3.4 shots, the same as Madison Keys and Ekaterina Alexandrova, fewer than Clara Tauson or Donna Vekic. A bit of a paradox is emerging here: Kenin has an impressive range of all-court and defensive skills, but she doesn’t play like it.

Is she a… servebot?

The American doesn’t seem like a weak returner. Aggressive, yes. Too aggressive, maybe. But any woman with such an effective backhand should be able to post decent numbers against the serve.

Yet: It is a constant struggle to break serve. The typical player in the WTA top 50 breaks 37% of the time. Swiatek grades out at 45.5%, and several more women top 42%. Pegula stands at 38.5%. Kenin, at 30.3%, ranks 48th of 50. Here are her peers at the wrong end of the list:

Player                Break%  
Lulu Sun               19.7%  
Linda Noskova          28.4%  
Sofia Kenin            30.3%  
Katie Boulter          30.8%  
Clara Tauson           31.2%  
Magda Linette          31.5%  
Xin Yu Wang            32.0%  
Donna Vekic            32.6%  
Ekaterina Alexandrova  32.9%  
Barbora Krejcikova     33.1%

Judging by some of these names, Kenin might be able to sneak into the top 20 with this return game. Vekic is 20th on the WTA points table. Tauson is 21st.

If there’s one characteristic that ties many of these players together, it is that their results run hot and cold. Krejcikova has won two slams but often struggled to get past early rounds. Noskova is a nightmare for Iga but manageable for others. Low break rates mean that the margins will always be narrow: Good for upsets and the occasional hot streak, bad for any semblance of consistency.

Kenin essentially takes the racket out of her own hands. Of players with at least ten matches in the charting database over the last year, only Danielle Collins puts fewer returns in play:

Player                  RiP%  RiP W%  
Danielle Collins       61.9%   55.7%  
Sofia Kenin            62.5%   54.0%  
Ekaterina Alexandrova  63.2%   58.3%  
Amanda Anisimova       64.3%   58.9%  
Alycia Parks           65.9%   59.6%  
Linda Noskova          66.4%   53.9%  
Liudmila Samsonova     66.9%   56.6%  
Barbora Krejcikova     67.3%   53.9%  
Bianca Andreescu       67.4%   54.4%  
Madison Keys           68.1%   57.6%

A lot of these names are starting to look familiar. As with the FHP/BHP lists, Kenin shares space with some of the game’s biggest hitters, even if I wouldn’t think of her that way. Maybe she disagrees: She certainly takes chances on return as if she does.

Yet the results aren’t there. The rightmost column, winning percentage on returns in play, shows that Kenin trails Collins, Alexandrova, Anisimova, and most of the rest by a healthy margin. She is roughly equal to Noskova and Krejcikova, though the Czechs get more balls back to start with. It’s fine to win 54% of points if the denominator is big enough–to take one example of many, Paula Badosa stands at 52%–but Sonya loses too many points without forcing the server to hit even one more ball.

As for the question in my subhead: No, Kenin isn’t really a servebot. Her serve itself ranks in the middle of the pack. But alas, her return stats are better suited to someone with a much more powerful first strike.

Same as the old Kenin?

It is tempting to conclude that Sonya’s 2020 was a remarkable streak of luck. She won the Australian Open after sneaking past Ashleigh Barty in the semi-final, winning fewer than 51% of points. She picked up the Lyon title a month later with four three-setters and five tiebreaks. She reached the Covid Roland Garros final even though Samsonova won more points than she did in their first-round encounter.

On the other hand, Kenin is a fundamentally different player than she was five years ago. One indicator is her now-languishing break rate:

Year  Break%  
2018   34.0%  
2019   34.0%  
2020   34.7%  
2021   33.9%  
2022   23.3%  
2023   31.5%  
2024   28.3%  
2025   30.9%

34% or 35% isn’t great, but it’s worlds apart from where she is now. Rybakina, while off her own peak lately, gets by with just 36%.

Back then, the American wasn’t so quick to pull the trigger. Based on the 17 matches we have in the charting database, her average point in 2020 lasted 4.1 strokes, another sharp contrast to her 3.4 of the last 52 weeks. 4.1 is at or above tour average, equal to Coco Gauff’s usual mark.

A big part of the difference is that she put more returns in play. In those 2020 matches, she got 71.7% of serves back, nearly ten percentage points higher than her current rate. She also won more of those points:

Span      RiP%  RiP W%  
2020     71.7%   55.0%  
Last 52  62.5%   54.0%

By just about every metric I have, Kenin is more aggressive now than she was at her best, and the strategy isn’t paying off. Perhaps she feels that she has to hit harder–or at least adopt tactics that mimic her more powerful peers–to keep up. Maybe she has lost a bit of quickness: Ankle and foot injuries sidelined her for much of 2022.

2020-era Sonya, then, is not back. Her form over the last six months suggests she might have landed on something that will work, if not anywhere near her peak level. The stats keep telling us she’s just like Alexandrova, and the risk-taking Russian has spent years in the top 30, picking up a title every year or so and making trouble for her higher-ranked peers. Kenin is on track to do the same.

Yet unlike Alexandrova, Anisimova, and the rest, Kenin is a former slam champ, with memories of an entirely different level of tennis. Performances like Tokyo and Charleston suggest she is getting closer to recapturing that magic. If she starts getting more serves back, then it’s time for the rest of the tour to worry.

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The Inscrutable Magic of Jessica Pegula

*Jessica Pegula playing defense at the 2022 US Open*

Alright, alright, alright.

When I started writing these player-themed pieces more than a year ago, Jessica Pegula was at the top of my list. One of my goals is to demystify the factors that cause each player’s success, or lack thereof. Pegula has had plenty of success, but compared to her peers at the top of the game, it is difficult to say exactly why.

There’s no obvious calling card that intimidates opponents. Pegula doesn’t serve very hard, ranking in the middle of the pack at least year’s US Open with an average serve speed around 92mph and first serves at 99mph. She doesn’t hit many aces. She ranks just outside the top ten in hold percentage, largely because she cleans up on second serves. That’s her one standout, top-line stat: In the 52 weeks leading up to Indian Wells, she won 51% of second-serve points. Only four women have topped 50%, and only Iga Swiatek wins more.

Pegula’s return numbers are even more anonymous. She ranks 20th among the WTA top 50 in break percentage. Top 20 on both sides of the ball is outstanding and unusual, but again, hardly intimidating. Whether serving or returning, she isn’t particularly effective on break points. Not that she’s bad in that department, but clutch play doesn’t help us understand all the match wins.

But win matches she certainly does. The American has held a place in the top ten since June 2022, much of that time in the top five. She has won seven tour-level titles and reached finals at both the US Open and the year-end championships. Off a title in Austin, she’s on a seven-match winning streak going into today’s match against Elina Svitolina. Elo isn’t quite as excited about her performance, but even that metric places her seventh, only 16 points behind fifth-place Qinwen Zheng.

What, then, is Pegula doing so right? When a player gets better results than her tools seem to suggest, I tend to fall back on difficult-to-quantify assets like movement, anticipation, and the blackest box of all, tennis IQ. Pegula excels in all those categories. But can we do better?

Second thoughts

Let’s start with the second serves. Here’s a generic theory for you: second-serve win percentages are related to success rates on return. Few women have dominant second serves–remember that Pegula is one of only a handful who win more than half of those points–so especially if the returner puts the ball in play, the server is already on defense.

Indeed, there’s something of a relationship, though not a statistically strong one. This plot shows the WTA top 50 in both categories:

Here’s a sentence I didn’t expect to write: Pegula and Sabalenka are almost identical in this pair of metrics. To go a step further, the cluster of players extending from Alexandrova in the lower left, to Sabalenka, then to Swiatek in the upper right, is disproportionately made up of big hitters. (The finesse players, along with the always unpredictable Jelena Ostapenko, are in the lower right.)

Yet by the standards of women’s tennis in the 2020s, Pegula is not a big hitter. It’s natural enough that she would equal Sabalenka’s return results, even if they get there in different ways. But second serves, too?

After watching Pegula’s quick dismissal of Xinyu Wang on Sunday, I thought I had the answer. While her second serves aren’t fast (79mph on average at last year’s US Open), they are precise. She doesn’t tee them up down the middle, and she manages to hit targets close to the service line. Location can be as valuable as raw speed, so that might explain how she gets the results of a bigger server.

Except… I can’t prove that she does any of that on a consistent basis. US Open scorers classify serve depth as “close to the line” or “not close to the line. Pegula merited a “close to the line” designation on 15% of her second serves, compared to a tournament average of 18%. She was slightly below average on first serves, too.

As for serve direction, it’s the same story. The Match Charting Project classifies each serve as one of three directions: wide, body, or down-the-tee. The average server hits one of the corners (wide or tee) with about 80% of their second serves. Pegula’s number is 74%. That’s not in itself bad–Venus Williams sports the same number–but it certainly doesn’t support my theory.

If there’s a quantifiable reason why Pegula wins all those second-serve points, it doesn’t look like we’ll find it in the second serve itself.

The match and the territory

Another eye-test hypothesis about Pegula: She doesn’t wait for the game to come to her. She stands as close to the baseline as she can get away with, both returning serve and in rallies. She doesn’t back up when faced with a deep drive or a high bounce. Depending on the shot, she’ll pick it up on a short hop or reach above her shoulder.

Not everyone is able to do this. For those who can, the advantages are clear. The earlier you hit the ball, the faster it gets back in your opponent’s court–and the less time they have to react. It’s power tennis for women without overwhelming power.

This style of play is particularly effective against opponents who aren’t particularly aggressive. Pegula’s losses this year have come against Madison Keys, Olga Danilovic, Ekaterina Alexandrova, and Linda Noskova: a quartet of heavy hitters who end points fast. Pegula lost just two matches on North American hard courts last summer, both to Aryna Sabalenka.

Against less free-swinging foes, the American takes away chances. Pegula doesn’t hit an overwhelming number of winners: 6% of her groundstrokes go untouched, in line with tour average. But her opponents do worse. In the Austin final, McCartney Kessler scored winners on just 2% of her shots from the baseline, half her usual rate. Pegula applied the same pressure to Xinyu Wang Sunday, slashing the Chinese player’s groundstroke-winner rate to 4% from a career average of 7%.

Again, these are stats that invoke parallels with a different style of player. The best way to prevent winners is to hit winners of your own, or at least end the point trying. That’s the Keys/Alexandrova/Ostapenko/etc playbook. Yet by Aggression Score, a metric that puts those ball-bashers on top, Pegula is below average, keeping company with the likes of Emma Navarro and Mirra Andreeva.

Deep research

Maybe you’re convinced that this explains a lot of Pegula’s success. She hugs the baseline, cuts off angles, and takes away opportunities for all but the most aggressive players to find openings of their own.

Still, I’d like more support from the numbers. Positioning is tricky to quantify, so I want to focus on one specific situation. What happens when the American is faced with a very deep service return?

Deep returns essentially erase the server’s advantage, neutralizing the point with one swing. The server usually needs to take a step or two back, and unless it’s a perpetual gambler like Ostapenko, she won’t try anything flashy for at least one more shot. Pegula doesn’t aim to end the point, either, but she’s less likely to concede territory. While that doesn’t allow her to seize the advantage, she’s careful not to hand too much of an edge to the returner.

Yet… nope. The next table shows how the ten players with the most hard-court data since 2022 handle deep second-serve returns: How often they get the next ball back in play (“3rd-inPlay”), how often those balls in play result in points won (“inPlay W%”), and how often they win points against deep returns, even considering the ones they didn’t get back (“vsDeep W%”).

Player            3rd-inPlay  inPlay W%  vsDeep W%  
Iga Swiatek            84.2%      59.8%      50.4%  
Aryna Sabalenka        77.5%      63.5%      49.2%  
Karolina Muchova       84.2%      56.3%      47.4%  
Paula Badosa           84.2%      54.6%      45.9%  
Elena Rybakina         79.5%      57.5%      45.7%  
Daria Kasatkina        85.5%      52.2%      44.6%  
Coco Gauff             83.6%      53.2%      44.5%  
Jasmine Paolini        82.7%      53.7%      44.4%  
Jessica Pegula         81.9%      53.2%      43.6%  
AVERAGE                81.8%      53.0%      43.4%  
Qinwen Zheng           76.5%      52.6%      40.2%

Pegula is almost exactly average, which makes her less effective against deep second-serve returns than most other top players. (The average considers all players, not just those listed, which is why it’s so close to the bottom.) Sticking to the baseline might still be the best solution for her, but it doesn’t win her an unusually high number of points.

This is a lot of negative results for one post. Pegula is close to the best in the business at turning her second serve into points won. But it’s not because she hits her seconds deep, or because she keeps the ball away the returner, or because she handles deep returns unusually well.

So we’re more or less back where we started. The American does a lot of things well, or at least well enough that they are not liabilities. Among top 50 players, she is average or better in nearly every category, close to the top ten in a few. By my groundstroke potency metrics, FHP and BHP, she does even better: She ranks among the top 20 in both, one of the few players to do so.

That, apparently, is good enough for a place in the top five. With better, finer-grained stats, we might be able to isolate how Pegula turns court position into victory. For now, we can appreciate how she holds her own against opponents with more fearsome weapons. Her personal brand of flexible shotmaking is certainly working, whether we understand it or not.

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Is the Stefanos Tsitsipas Backhand Back?

On Saturday in Dubai, Stefanos Tsitsipas won his first 500-level title. Just about everything about this was unexpected. He had lost his last eleven finals at ATP 500s. He had dropped four of six matches coming into the event, including three against opponents outside the top 70. He barely deserved to be in the final at all, coming through a quarter-final against Matteo Berrettini in which he won a mere 47% of total points.

Most of all, the Greek shocked fans with the way he won. For the first time in years, his backhand was a weapon. He took big swings, especially on return of serve. The one-hander was suddenly so fearsome that Felix Auger-Aliassime, his opponent in the final, stopped attacking it. According to my backhand potency (BHP) metric, Tsitsipas’s performance in the semi-final against Tallon Griekspoor was his best on a hard court in more than two years.

For me, this is exciting. How often does a player–in his mid-20s, no less–just, out of nowhere, fix their biggest weakness?

One immediate cause is clear: Tsitsipas swapped out his Wilson racket for a stiffer-framed Babolat Aero. I’ll leave it to the gear experts to dissect exactly how much of a difference that has made. But given the Greek’s tactical shift this week, I have to think that the new racket offered a small boost. More importantly, it provided an excuse for Stef to make some long-overdue changes.

Let’s take a closer look at the new-and-improved Tsitsipas game.

Back(hand) from the brink

I wrote about Tsitsipas a year ago, after he crashed out of Indian Wells to Jiri Lehecka. I focused on Stef’s utter helplessness against first serves to his backhand. No one expects ATPers to win a lot of points against the first serve, but this was dire.

The Greek won just 12% of first-serve return points when Lehecka aimed at his backhand. His ten-match rolling average had fallen as low as 16% in that category, compared to career rates around 23%. At the 2023 Tour Finals against Jannik Sinner, Tsitsipas went oh-for-21 when the Italian first-served to his weaker side.

Of course, this was no secret. Most players mix up their serve direction evenly, rarely hitting more than 60% in either direction. In Acapulco last spring, Alex de Minaur hit 90% of his first serves to the Tsitsipas backhand. Most opponents didn’t go that extreme, but it must have been nice to know that there was a weak point to poke under pressure.

Until about a week ago, nothing had changed. Last fall in Basel, the Greek won barely 10% of first-serve return points when Arthur Fils aimed at his backhand. In Doha just two weeks ago, he salvaged only 15% against Hamad Medjedovic. Griekspoor nearly ousted him in Rotterdam by hitting 71% of his first serves in that direction. So the new look is truly sudden:

Match             1st to BH  inPlay  Pts Won  
Prev 10               56.5%   57.7%    23.2%  
QF vs Berrettini      67.7%   57.1%    19.0%  
SF vs Griekspoor      66.0%   54.8%    29.0%  
FI vs FAA             64.7%   72.7%    31.8%

The “previous ten” matches are those indexed by the Match Charting Project, and they run between Tokyo last year through the Medjedovic match. That span looks a bit better than early in 2024, when Tsitsipas’s win rate on these points nearly fell below 20%, but some of that is because he faced weaker servers. Apart from Fils, the span includes two matches against Alex Michelsen and one against Mattia Bellucci.

The Berrettini result doesn’t look like much of an improvement (and again, he won only 47% of points in that match), but it is Matteo Berrettini we’re talking about. Against two more strong servers, Tsitsipas not only leapt beyond his own recent rates, he exceeded tour average. The typical player wins 28% of these first-serve return points. Stef did better.

The Auger-Aliassime result is particularly telling. While Stef has now won seven of ten meetings, Felix has piled up some impressive serve numbers over the years. In Marseille in 2022, the Greek won only 12% of first-serve return points on his backhand side. Back in 2019 when the pair met at Indian Wells, Auger-Aliassime sent 21 first serves in that direction, and Tsitsipas won the point only once.

Back(hand) up

The challenge for every returner is to find a balance between swinging big and playing it safe. Tsitsipas, with his fluctuating confidence in the topspin backhand, sometimes leans too hard on his slice. Slice returns aren’t themselves bad–a deep slice return can instantly snatch the advantage away from the server–but Tsitsipas is rarely the stronger baseliner on court. Settling in for a baseline rally is, for him, a losing proposition.

Surprisingly, Stef’s three matches in Dubai do not reflect a change in overall shot selection. From the time I wrote about his backhand struggles last year, he began hitting more and more topspin first-serve returns. Since the European indoor swing last fall, the rate has drifted back down again, though not as far as its low point, which was probably driven by injury.

This graph shows how often Tsitsipas chose to hit topspin backhand returns (as opposed to chips or slices) against first serves. It shows a ten-match rolling average on hard courts, across more than 130 charted matches since 2018:

The current rate is almost exactly at his career average of 56%. Perhaps that understates his current approach a bit–as noted, he faced some big servers in Dubai, and he’ll always end up hitting more slices to defend against players of their caliber.

This was the biggest surprise for me in the numbers. Tsitsipas looked like a completely different player last week. His backhand returns may well have been qualitatively different. But he didn’t try to attack more of them than usual. The same was true in rallies. His career backhand slice percentage (compared to all backhands) is about 20%, and he continued to land in that range for the final three rounds in Dubai.

Back(hand) in black

This is where I get to say that, yes, the margins in tennis are small. Stef’s one-hander racked up points against Griekspoor, rating 5.5 on my BHP scale. (His average over the last 52 weeks is negative, and no one consistently scores as high as Tsitsipas’s rating in that match.) But against Berrettini, his BHP was slightly negative, and against Auger-Aliassime, it was neutral.

The backhands generated by the Greek’s blacked-out racket made for glittering highlight reels. Yet they do not fully explain the title run. Tsitsipas survived the quarters by the slimmest of margins. He dropped 53% of points and probably would’ve lost the match had it not been for a miraculous half-volley winner at 4-all in the decider. The semis, yes, credit to the backhand in all its glory. The final: unusually steady backhand returns that led a flummoxed Auger-Aliassime to target the Tsitsipas forehand instead.

Assuming Stef adopts his new stick and continues to swing freely with it, the best-case scenario is probably a backhand that is … well, average. Average is not a bad thing! Tsitsipas is one of the elite servers on tour, peaking at an 89% hold rate in 2023. His forehand is a reliable weapon. A year ago, it looked like he was becoming a one-dimensional servebot. He may now be able to avoid that fate.

Where, then, is the equilibrium? Opponents have long feasted on the Tsitsipas backhand, and they won’t give up so easily. Expect servers to push him out wide, where he’ll be stuck continuing to slice. Baseliners will test him to see if they can break the shot down. After years of backhand struggles, both mental and physical, I don’t expect he’ll come through unscathed.

But he doesn’t need to transform into Novak Djokovic. The Greek’s backhand has long been among the bottom third on tour. A step up to average would be worth a point or two per match, something that, at the margin, is the difference between a berth at the Tour Finals and another year-end ranking outside the top ten. Tsitsipas has said he wanted to inspire more youngsters to hit one-handed backhands. Winning more matches would be an excellent way to do that.

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Elina Svitolina Plays Hard

*Elina Svitolina at the 2020 Australian Open. Credit: Rob Keating*

Here’s a stat to get us rolling: In yesterday’s fourth round match at the the Australian Open, Elina Svitolina won 67% of points when she hit a backhand. Tour average is a neutral-as-its-gets 50%. Svitolina, with her resourcefulness off that wing, averages 51%.

It gets even better. Usually, if a rally statistic comes out much above 50%, it’s because it’s loaded with winners. But against Veronika Kudermetova yesterday, Svitolina hit just one backhand groundstroke winner. She induced two more forced errors, but committed five unforced errors of her own. All of which is to say, those point-winning backhands came thanks to point construction, not swinging for the fences. (An erratic Kudermetova helped, too.)

The backhand masterclass, on the heels of another strong baseline performance against Jasmine Paolini in the third round, recalls Svitolina’s peak. The Ukrainian is now 30 years old, veteran of innumerable injuries, a pregnancy, and the perpetual distraction of her country at war. My Elo ratings suggest that she was at her best nearly seven years ago, after she upset Simona Halep for the the 2018 Rome crown. That’s an eon in tennis time: She hasn’t held a place in the top ten since 2021.

Yet here she is, in the Melbourne final eight. It’s her twelfth major quarter-final, her fourth since becoming a mother. She might have made it one more a year ago. After a grueling runner-up finish in Auckland to open her 2024 campaign, Svitolina raced through three rounds at the Australian before retiring to Linda Noskova in the fourth round. This year, she skipped the warmups and has sustained her best tennis on the bigger stage. With Madison Keys across the net tomorrow, she has a chance to go even further.

Svitolina 2.0 will probably never reach the level she showed in the mid-2010s. She’s a half-step slower, and she needs to manage her schedule with care. But like all players with successful second chapters, she has changed her game in response to her limitations. She is, and always will be, a counterpuncher, leaning on one of the game’s sturdiest backhands. Yet the new Elina has first-strike weapons that her younger self could only dream of.

Hitting big

While no one is about to mistake her for Aryna Sabalenka at the service line, the 30-year-old does more damage than she used to.

Yesterday against Kudermetova, Svitolina averaged almost 103 miles per hour (165 kph) on her first serves. I have first-serve speed for more than 70 of her career slam matches, and she hit that level in only five of them, mostly at Wimbledon. When she reached the quarters at the 2021 US Open, she averaged less than 100 miles per hour in all five matches.

It’s a small improvement, but coupled with increased precision on the first serve, it is paying off. In the sample of Match Charting Project-logged matches, she converted more plus-ones behind her first serve in 2024 than her career rates. Even her improved 2024 marks pale in comparison to what she has done in Melbourne:

Span               Unret%  <=3 W%  
Career              27.2%   38.6%  
2024                27.5%   41.9%  
R3 vs Paolini       36.1%   60.6%  
R4 vs Kudermetova   39.4%   63.9%

The second column, showing the percent of first-serve points in which Svitolina won the point with her serve or second shot, is where players make their money. No matter how good your ground game, it's tough to make up a deficit in the cheap-points category. Through 2024, the Ukrainian was middle-of-the-pack in both of the stats. The form she has shown in the last few days is something entirely different.

The numbers are particularly impressive against a defender like Paolini. While the Italian probably isn't as strong as her #4 ranking suggests, she is certainly an elite returner. In charted matches last year, she put nearly three-quarters of first serves back in play. Svitolina allowed her only 64%. And as we see with the serve-or-second-shot stat, Paolini couldn't do much when she did get the ball back. On average, the Italian wins more than half of the first-serve points in which she lands her return. On Friday, she won just 6 of 23.

There's just one reservation about the third-round performance. Svitolina got those results by taking chances, and she made fewer than half of her first serves. It was a day of extremes: 48% of first serves in, 83% of first-serve points won, and 42% of second-serve points won. Had she explicitly targeted a more typical 60% rate of first serves in, she wouldn't have posted the same win rates. But with a first-class returner across the net, Svitolina's tactics were proven correct.

That half step

So far we've talked about what the Ukrainian can control. Just as important is what she can't: The aging process and its effect on the rest of her game.

Here's an overview of how her current level compares to her 2017-20 peak, measured by first-serve and second-serve win percentages, along with return points won:

Span     1st W%  2nd W%   RPW%  
2017-20   66.6%   47.2%  46.1%  
2023-25   65.5%   46.8%  45.2%

Approximately a one-percentage-point drop across the board. That makes sense as an explanation of the difference between a player ranked around #5 and one who should be hovering around #20. (Elo is more optimistic than Elina's official ranking of #27.)

Now try the same stats, hard courts only:

Span     1st W%  2nd W%   RPW%  
2017-20   67.5%   47.3%  46.1%  
2023-25   68.9%   47.9%  43.6%

At her peak, Svitolina was basically the same player on all surfaces. Now, she sports a different type of surface profile. The service aggression is paying off, while she seems to be struggling to do return damage on faster courts.

The 30-year-old has always aimed to get a lot of serves back. According to MCP data, she has put 77.5% of serves in play, a number that fell to 76.4% last season. Both marks are near the top of the table. Players who adopt such a defensive posture usually don't win a particularly high rate of those points, and Svitolina is no exception: Her 51.5% win rate when she puts the return in play is roughly tour average. It's a low-risk, fairly-low-reward strategy.

Against strong servers, the results can be bleak. She got fewer than 65% of serves back against Sabalenka in Cincinnati last summer, and even Ons Jabeur held her to 67% at Wimbledon. In Adelaide three years ago, Madison Keys was so strong from the line that Svitolina put only half of returns in play. At her peak, it was rare for the Ukrainian to fall below 70%.

Her hard-court results, then, depend a great deal on the matchup. The relatively punchless Paolini was a lucky draw in this regard. Once the serve and the plus-one are past, Svitolina can go toe-to-toe with anybody. She won 60% of points that lasted four or more strokes against the Italian. Facing Kudermetova, as we've seen, it was even easier. Once Elina got her racket on a backhand, the Russian basically gave up.

It's a mad, mad quarter-final

Svitolina's next challenge is entirely different. In five career meetings, she has two victories against Keys, coming at the Australian Open and US Open in 2019. Even when she was younger, she couldn't neutralize the American's serve. She has won about 36.5% of return points in their head-to-head, never topping 43.3% in a single match.

The margins for the Ukrainian tomorrow will be slim. While Svitolina has boosted her serve, she has gained more plus-one points than unreturned serves. That works against opponents like Paolini, but Keys swings big at everything, including hard serves. In the Adelaide final against Jessica Pegula--a broadly similar player to Svitolina--Keys held her opponent's serve points to an average of 3.1 strokes. That's a lot of short "rallies," and it means fewer chances for Elina to put away a weak second ball.

Svitolina will find herself even more powerless on return. As we've seen, Keys is responsible for one of the worst performances of her career. In that 2022 Adelaide match, the 30-year-old won a miserable 22% of return points. The longer the rally, the better for Svitolina. But Keys will try to prevent the commentators from using the word "rally" at all. In the Adelaide title match, the American's service points lasted, on average, a mere 2.6 strokes.

The Ukrainian may not have much control over the proceedings, but that isn't to say she doesn't have a chance. My forecast leaves her plenty of room, giving her a 42.5% shot at reaching the final four. Keys's aggression often goes astray, and nagging injuries could hamper either player. If the American can't serve at 100%, or if she falls back on more passive tactics, the underdog will pounce. In longer points, Svitolina is the clear favorite. She'll have to hope she gets the chance to play some.

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This Is What a Dangerous Madison Keys Looks Like

*Madison Keys in 2023. Credit: Hameltion*

Last year, Madison Keys missed the Australian Open with a shoulder injury. She ended up playing barely half the season, missing more time after tearing a hamstring at Wimbledon. She still won enough matches to head to Melbourne as the 19th seed at this year’s first major.

She’s better than that.

In one sense, I’m just stating the obvious: She beat Jessica Pegula for the title in Adelaide on Saturday and moved up to 14th on the WTA computer. Beyond that, anyone who can hold on to a spot in the top 20 despite missing so many events is probably better than their ranking. Elo agrees, rating Keys ninth among women, a modest 33 points behind fifth-place Elena Rybakina.

Even more striking is the way the American won the Adelaide championship. She served as well as she has in years, indicating that the shoulder is fully healed. She played extremely aggressively, a style that she has never shied away from, but that she sometimes struggles to maintain. Finally, Keys did all that while posting excellent return numbers. The 29-year-old is a two-time semi-finalist at the Australian Open, and if she keeps this up, she could easily make it three.

The serve is back

When everything clicks, no one on tour–with the possible exception of Rybakina or Aryna Sabalenka–makes serving look so easy. Keys doesn’t just slam flat serves down the tee: She adds a bit of side spin, so her inch-perfect deliveries look like they’re sailing slightly wide until after they cross the net. Then she employs the same spin to send wide serves even wider. When she misses, she can fall back on some of the heaviest topspin seconds in the women’s game.

Whether the shoulder was still shaky or the hamstring compromised her motion, the American struggled to maximize her serve as late as last year’s US Open. In her third-round loss to Elise Mertens, her average first-serve speed was just under 99 miles per hour. Out of nearly 100 grand slam matches for which I have serve speed data, it was only the second time–the other was 2017 Roland Garros–that she hit firsts so slowly.

Today in her Melbourne opener against Ann Li, her average first serve was 109 miles per hour. That’s the fastest I have on record for her since 2015.

I don’t have serve speeds for Keys’s victories last week in Adelaide, but the results hint at numbers well into triple digits. In the final against Pegula, she hit 10 aces, good for 13% of her serve points. Facing Liudmila Samsonova in the semis, she smacked 12 aces–17% of serve points. In a short quarter-final against Daria Kasatkina, she tallied 11 aces, an eye-popping 21% of serve points. It was only the fourth time in the 2020s that Keys topped the 20% mark and the only time in her career she managed it against a top-ten opponent.

Adelaide marked the first time since 2019 that the American aced at least 10% of her service points in three consecutive matches. She hadn’t done so at a single event since 2016.

Aces are great in themselves, but the stat is particularly useful for representing the serve’s effect on even more points. Yes, Keys won 13% of her serve points against Pegula with aces, but 41% didn’t come back. That’s another sign of a revival: In dozens of Match Charting Project-logged matches, it’s the first time she’s topped 40% in that category since the Australian Open in 2022–her most recent semi-final run Down Under.

The American mitigated her shoulder woes last year by starting points more conservatively. She wasn’t as deadly with her first serve, but she landed more of them. Among the WTA top 50, only Elina Avanesyan and Yulia Putintseva missed fewer first serves. If Adelaide is any indication, it’s back to business as usual, taking a few more risks and wreaking absolute first-serve devastation:

Span        SPW  1stIn  1st W%  2nd W%  
Adelaide  65.4%  63.4%   71.6%   54.8%  
2024      60.6%  68.2%   66.7%   47.4%

It’s not an apples-to-apples comparison, because the 2024 line contains plenty of clay-court matches, including two against Iga Swiatek. But the difference is sufficient to tell the story anyway. 60.6% of serve points won was good for 8th-best on tour last year. 65.4%, on the other hand, is almost two percentage points better than anyone posted on hard courts. The 71.6% first-serve win rate would have put her in the top five, and no one came close to winning 54.8% of their second serves.

I don’t want to put too much emphasis on a single tournament–everybody looks good if you turn the microscope on a great week. But it’s worth offering one more tidbit in Keys’s favor. She posted those numbers against extremely strong opposition. Her five victims in Adelaide were ranked 16th, 17th, 9th, 26th, and 7th, respectively. That’s a tougher schedule that any player faces over the course of an entire season. If Madison does reached the Melbourne semis, it’ll be an easier path than she faced to collect the trophy in Adelaide.

Swinging freely

Keys has improved her return game over the years, and she’s gotten more comfortable playing long rallies. One of the more surprising numbers on her stat sheet is that she has a better winning percentage on clay than on hard courts.

Still, she’s an aggressor at heart. Her serve isn’t the only shot she can hit as hard as anyone, nor is it the only weapon she can land on the line. Generally speaking, the more aggressive she is, the better her results. The shoulder and hamstring injuries forced her to play more conservatively. That is now over.

In less than an hour on court with Kasatkina, she crushed, by one count, 38 winners. Facing Pegula on Saturday, she tallied 40. I have winners and unforced errors for about one-quarter of her career matches, and the Adelaide final was the first time she cracked 40 winners since 2019. It wasn’t uncontrolled either. The opposite side of the ledger was a respectable 27 unforced errors, good for a ratio of 1.5. Even in her Auckland loss to Clara Tauson the previous week, she recorded 38 winners against 30 unforced, a ratio that would win most WTA matches.

The best indicators of the American’s renewed attack are the various metrics for aggression. By Rally Aggression Score–a measure of how often a player ends points for good or ill after the return of serve–she rated +147. (Average is 0, and almost all players fall between -100 and 100.) Return Aggression Score–the same idea, but strictly for returns of serve–put her at +137. Her career averages are around +100, but in 2024, she fell below +60 in both.

The last time that Keys reached +137 or higher by both measures was the 2019 Cincinnati quarter-final, when she beat Venus Williams en route to the title.

We keep finding things that Keys has done for the first time since 2019. They almost all go back to that week in Cincinnati. (Coincidentally, she straight-setted Kasatkina there, too.) With the possible exception of her 2017 US Open final run, the Cincinnati effort was the best of her career. She has found that form again.

Keys to the match

One difference between 2019 Cincinnati and 2025 Adelaide: The American returned a whole lot better last week. She won 48.1% of return points in Adelaide, compared to 43.7% in Cinci.

It’s rare for players to substantially improve their return game once they arrive on tour. The rest of the tour learns how to beat you, the opposition gets stronger, and age slows you down. Yet Keys, in her late 20s, has gotten better:

While the 2025 data point probably won’t stick above 47%, the 2023 and 2024 results demonstrate the trend. Last year, Keys’s 44% mark was better than half of the top 50, a strong showing for a serve-first player. Return points are an extreme case of tennis’s small margins. By top-50 standards, 43% of return points is weak, 44% is adequate, and 45% is strong.

47%–the American’s success rate in Auckland and Adelaide–is beyond elite. Only two players–Coco Gauff and Marketa Vondrousova–did better than that on hard courts last year.

It will take some time before we know whether Adelaide was an outlier or a harbinger of a resurrected career. Keys’s 2025 season will surely fall somewhere in the middle, at least if she remains healthy. There are certainly reasons for optimism. For the most part, she’s done all of this before, serving and attacking her way into the top ten as far back as 2016, and returning better in the last two years. If those two halves come together, we won’t see a (19) next to her name again for a long time.

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Mirra Andreeva’s Many Happy Returns

*Mirra Andreeva at the 2024 Paris Olympics.*
*Credit: Like tears in rain*

Mirra Andreeva is the best teenager on the WTA tour, and it isn’t close. She’ll finish 2024 ranked 16th on the official points table, more than one hundred places ahead of her closest teenage competitor, Maya Joint. Andreeva is a year younger than Joint, and she’s two years younger than Ella Seidel, third on the under-20 list.

Players who outpace their fellow teenagers typically go on to notable careers. Here’s the list of top teenagers at the end of each season this century:

Year  Player                    Rank  
2000  Serena Williams              6  
2001  Kim Clijsters                5  
2002  Kim Clijsters                4  
2003  Vera Zvonareva              13  
2004  Maria Sharapova              4  
2005  Maria Sharapova              4  
2006  Maria Sharapova              2  
2007  Nicole Vaidisova            12  
2008  Agnieszka Radwanska         10  
2009  Caroline Wozniacki           4  
2010  Anastasia Pavlyuchenkova    21  
2011  Christina McHale            43  
2012  Sloane Stephens             38  
2013  Eugenie Bouchard            32  
2014  Madison Keys                30  
2015  Belinda Bencic              14  
2016  Daria Kasatkina             26  
2017  Catherine Bellis            46  
2018  Dayana Yastremska           58  
2019  Bianca Andreescu             5  
2020  Iga Swiatek                 17  
2021  Emma Raducanu               19  
2022  Coco Gauff                   7  
2023  Coco Gauff                   3  
2024  Mirra Andreeva              16

There’s no such thing as a can’t-miss prospect in women’s tennis, but showing up on this list gets you pretty close. Andreeva’s case is particularly extreme, because she is still just 17 years old.

In the under-18 category, the young Russian has virtually no competition. Only three other under-18s rank among the top 200, none closer than Alina Korneeva at 176th. No woman so young has finished inside the top 20 in almost two decades, going back to Nicole Vaidisova’s top-ten showing in 2006.

Here’s another way to look at what Andreeva has accomplished. With four victories to reach the Ningbo final in October, she increased her career tour-level main-draw win count to 48. Take a look at the list of all women, post-Vaidisova, to post even 30 such wins before their 18th birthday:

Wins  Player              Last Win as 17yo  
32    Victoria Azarenka         2007-07-30  
47    Caroline Wozniacki        2008-06-23  
42    Tamira Paszek             2008-09-15  
32    Donna Vekic               2014-06-23  
33    Amanda Anisimova          2019-07-29  
64    Coco Gauff                2022-03-07  
48    Mirra Andreeva            2024-10-14

Again, good company, and think of all the stars who aren’t here. You know, everybody (besides Vekic) for a decade. In this entire time span of about 17 years, Andreeva has done more at her age than anyone except Coco Gauff. The Russian might even erase that caveat. She doesn’t turn 18 until the end of April, and this year, she had won 12 matches by that time. 17 wins–enough to surpass Gauff–is hardly out of reach.

Let’s turn now to how Andreeva is achieving so much success, and why she might soon lop a digit off of her age-defying ranking.

Returns first

Forget about all this under-18 and teenager stuff for a minute. Mirra is already one of the best returners in the game. Here are the top dozen WTA tour regulars, ranked by return points won:

This isn’t a perfect measure. For one thing, Andreeva faced one of the weaker schedules of players on this list. Her median opponent was ranked 58th, compared to 30th for Iga and 42nd for Coco. It would take considerably more work to suss out whether Andreeva’s 47.3% of return points won, against her set of opponents, is better or worse than, say, Aryna Sabalenka’s 45.3% against competition nearly as stiff as Swiatek’s.

The quibbles mean that we can’t quite proclaim the Russian a top-three returner. The point, though, is that she’s in the conversation. In fact, if we narrow our view to matches against top-20 players–limiting if not eliminating the influence of each woman’s schedule–Andreeva hangs on to her position:

(We’re not talking about Iga today, but… 47% of return points won against top-20 opponents? My word.)

Where Andreeva shines even brighter is against first serves. She won first-serve return points at a higher clip than any other woman on tour this year:

Player               1st RPW%  
Mirra Andreeva          42.6%  
Coco Gauff              42.1%  
Marketa Vondrousova     40.8%  
Iga Swiatek             40.8%  
Daria Kasatkina         40.7%  
Marta Kostyuk           40.5%  
Elina Avanesyan         40.0%  
Jasmine Paolini         40.0%  
Katerina Siniakova      39.5%  
Karolina Muchova        39.5%

Put that in perspective: Andreeva wins more first-serve return points than Barbora Krejcikova (to pick one name from several) wins all return points.

Again, the Russian’s stats are influenced by her level of competition. Against top-20 opponents, Mirra falls to third place, behind Swiatek and just back of Gauff. But you get the idea. To say, “Well, actually, she’s not quite up to Gauff’s standard” is to say we’re dealing with a special player.

Precocious patience

Andreeva’s serve is good for a 17-year-old, but as we’ve seen, it’s not the side of her game that has put her in the top 20. Her returns, and by extension, her baseline play, are responsible for that.

Among top players, Mirra is currently most similar to countrywoman Daria Kasatkina. The two Russians, according to Match Charting Project data, post average rally lengths of 4.9 strokes, more than anyone else in the top 40. Both women are effective off both wings; Andreeva’s backhand is the better of the two, while Kasatkina’s forehand scores more points. The teenager is a bit more likely to force the issue: While both rank well below average in Rally Aggression Score, Mirra is closer to the norm.

A key difference shows up in their rally breakdowns. Again based on the subset of matches logged by the Match Charting Project, here are each woman’s percent of points won at various rally length categories:

Player     1-3 W%  4-6 W%  7-9 W%  10+ W%  
Andreeva    49.8%   48.6%   51.8%   53.8%  
Kasatkina   48.0%   45.6%   51.0%   52.5%

The first thing that pops out here is that Andreeva is better in every category, something that reflects both the vagaries of the uneven tennis schedule and the non-random nature of Match Charting Project samples. However you slice it, Mirra won more points, though my Elo rankings agree with the official formula that Kasatkina was the better player.

To get a better idea of what we’re looking at, let’s normalize each woman’s rally-category splits as if they won exactly half of their overall points:

Player     1-3 W%  4-6 W%  7-9 W%  10+ W%  
Andreeva    49.5%   48.3%   51.5%   53.5%  
Kasatkina   49.6%   47.1%   52.7%   54.2%

The teenager holds the edge in the 4-6-stroke category, while Kasatkina looks better in the longer rallies.

That 4-6-shot category tells us more than it lets on. Andreeva’s 48.3% (or the un-normalized 48.6%) doesn’t look very impressive. Points in this group account for one quarter of all the points she plays, and she loses more than half.

But consider her playing style. Medium-short rallies are often determined by the lingering influence of the serve: The returner might withstand a plus-one attack, only to leave a sitter for the server to put away. Or a strong return doesn’t finish the point, but the returner’s next shot–the fourth stroke of the rally–does the job. 4-6-shot rallies go disproportionately to big hitters: Aryna Sabalenka led the category this year.

For someone like Andreeva or Kasatkina, the task is to limit the damage. Get the serve back, try to neutralize the point. Place serves where aggressive returners won’t do too much damage. If a big return comes back, play the same defense that works against the serve. Kasatkina has all of those skills, but there is only so much she can do. Mirra, with her flatter strokes and somewhat bigger weapons, can keep opponents from running away with these medium-short points. She’ll lose sometimes to the likes of Sabalenka, but unless they catch her on an off day, she won’t be blown off the court.

Growth potential

If Andreeva could be characterized as a younger, somewhat more aggressive Kasatkina, that would be a pretty good compliment for a 17-year-old. But the teenager promises to become much more.

One of my favorite bits of counterintuitive tennis wisdom is that return stats rarely improve. Returning is based on a set of skills–anticipation, quickness, speed–that, on net, decline with age. Whatever tactical savvy a player picks up as she ages will, at best, cancel out the age-related decline. This isn’t an iron law, but it’s surprising how often players reach their peak return effectiveness very early in their careers.

The same is not true for the serve. 17-year-olds (or, hey, 23-year-olds) have the capacity to get stronger. Footspeed and reaction time don’t figure into the serve, so with better coaching or targeted practice (think late-career Djokovic), serve stats can improve even as the rest of a player’s game declines. A couple of examples: Maria Sakkari steadily improved her first-serve win rate from the 13th percentile to the 93rd percentile in five years. Simona Halep’s first-serve was in the top quarter of tour regulars in 2014; two years earlier, it had been one of the WTA’s worst.

The implications for Andreeva are clear. We don’t need to wishcast an improvement in her return game: She’s already one of the best returners in the game. Instead, the road to the top ten and beyond goes through her serve. Her results so far are adequate. She won 58.4% of her serve points in 2024, compared to a top-50 average of 58.7%. When we consider how much she played on clay, that number looks a bit better. On hard courts, she won more serve points than average.

Mirra, then, doesn’t face the same uphill struggle that Sakkari and Halep overcame. Her potential trajectory is more like, say, Victoria Azarenka’s. Vika arrived on the scene as a killer returner with a good-enough serve. In 2009 and 2010, she won nearly half of her return points against 58% to 59% of her service points. That combination earned her two top-ten finishes. (She was a few years older than Andreeva at that point, yet another reminder of how unique the Russian’s early success has been.)

Two years later, Azarenka boosted her rate of serve points won to 61%. Combined with the same results on return that had gotten her into the top ten, the bigger serve earned her six titles–including her first major–and the year-end number one ranking. 59% to 61% may not sound like much, but for an elite returner, that’s all it takes.

If Andreeva did the same, lifting her 58.4% serve-point win rate to 61%, she’d be the ninth-best server on tour. Remember how she’s just a tick behind Coco Gauff on return? A Vika-like serve boost would put her ahead of the American in that category, outweighing Coco’s narrow edge on return. Shorter version: She’d be a top-three player, maybe more.

None of this is guaranteed. It may not–it probably won’t!–happen right away. For every Azarenka, there’s a Nicole Vaidisova or, worse, an injury victim like Catherine Bellis. Still, few paths to the top are marked so clearly. For Mirra Andreeva, a modest, achievable set of improvements are all that stand between her and the top.

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