Forecasting Andy Murray, Doubles Specialist

We are three weeks into the mostly-triumphant doubles comeback of Andy Murray. In his first week back, he raced to the Queen’s Club title with Feliciano Lopez. A week later, he paired Marcelo Melo and lost in the first round. At Wimbledon, he is partnering Pierre-Hugues Herbert, with whom he has already defeated the only-at-a-slam duo of Marius Copil and Ugo Humbert.

Today in the second round, Herbert/Murray face a sterner test: sixth-seeded team Nikola Mektic and Franco Skugor. The betting markets heavily favored Herbert/Murray going into the contest, but we have to assume that punters (including an unusually high number of casual ones) are probably overrating the familiar name on his home turf.

D-Lo to the rescue

Let’s see what D-Lo (Elo for doubles!) says about today’s match. D-Lo treats each team as a 50/50 mix of the two players, and adjusts each player’s rating after every match, depending on the quality of the opponent. It also very slightly regresses both partners to the team average after each match, because it’s impossible to know how much each player contributed to the result.

Herbert is D-Lo’s top doubles player in the world on hard and clay courts, though he falls to 6th in the 50/50 blend of overall and grass-specific ratings used for forecasting. Murray, thanks to his run at Queen’s, is up to 54th in the blend, though that’s really more like 40th among players in the draw, since several injured and recently-retired players are clinging to high D-Lo ratings.

Mektic and Skugor are credible specialists, as indicated by their ATP ranking. They are 24th and 26th in the D-Lo, respectively. Combined, the two teams’ ratings are quite close: 1773 for Herbert/Murray to 1763 for Mektic/Skugor. In a best-of-three match, a difference of 10 points translates to a 51.4% edge for the favorites. In best-of-five, the better team is always more likely to come out on top, though with such a small margin it barely matters. Here, the best-of-five number is 51.6%.

Versus the pack

How does a team rating of 1773 compare to the rest of the remaining field? Entering Saturday’s play, 22 men’s doubles pairs were still in the draw. As I write this, Lopez and Pablo Carreno Busta are the only additional team to have been eliminated, reducing the field to 21.

Here are the combined D-Lo ratings of these teams. The rank shown for each player is based on the 50/50 blend of overall and grass rating used for forecasting.

Team D-Lo  Rank  Player             Rank  Player             
1873       2     Mike Bryan         3     Bob Bryan          
1858       4     Lukasz Kubot       7     Marcelo Melo       
1836       9     Raven Klaasen      10    Michael Venus      
1817       8     John Peers         17    Henri Kontinen     
1802       12    Nicolas Mahut      22    E Roger-Vasselin   
1788       18    J S Cabal          19    Robert Farah       
1773       6     P H Herbert        54    Andy Murray        
1764       15    Oliver Marach      36    Jurgen Melzer      
1763       24    Nikola Mektic      26    Franco Skugor      
1757       20    Rajeev Ram         33    Joe Salisbury      
1747       23    Horia Tecau        41    Jean Julien Rojer  
1709       42    Maximo Gonzalez    46    Horacio Zeballos   
1695       29    Ivan Dodig         88    Filip Polasek      
1681       58    Marcus Daniell     62    Wesley Koolhof     
1677       50    Frederik Nielsen   77    Robin Haase        
1644       81    Marcelo Demoliner  90    Divij Sharan       
1637       84    A Ul Haq Qureshi   99    Santiago Gonzalez  
1596       106   Philipp Oswald     123   Roman Jebavy       
1575       101   Mischa Zverev      184   Nicholas Monroe    
1533             Jaume Munar        216   Cameron Norrie     
1517       177   Marcelo Arevalo    214   M Reyes Varela

Herbert/Murray rank 7th among the surviving pairs. The combined rating of 1773 makes them competitive against anyone. The 100-point difference separating them and the Bryans gives them a 33% chance of pulling off a best-of-five upset, while the 29-point gap between them and Nicolas Mahut/Edouard Roger Vasselin translates to a 45/55 proposition.

Fortunately for the French-British pair, they won’t have to play a higher-rated team for some time. If they win today, they’ll face the winner of Dodig/Polasek vs Zverev/Monroe. The first of those teams is rated 80 points lower than Herbert/Murray (64% odds for the favorites), and the second is 200 points lower (81% for the faves). The three teams that could advance to become the quarter-final opponent for Herbert/Murray are all rated lower than Dodig/Polasek.

The draw certainly favored Sir Andrew. Yes, the 1859-rated Pavic/Soares duo crashed out in their section, but even before that, three of the best teams–Bryan/Bryan, Kubot/Melo, and Mahut/Roger-Vasselin–were stuck together in another quarter. While no men’s doubles match is a sure thing, the path is clear for Herbert/Murray to reach the final four.

Beyond Wimbledon

Does Murray have what it takes to become a full-time doubles specialist? Taking his Queen’s Club title into account, his overall D-Lo is already up to 36th best on tour, just ahead of Skugor, and several places better than Roland Garros co-champ Kevin Krawietz. Jurgen Melzer, another excellent singles player making of a go of it on the doubles circuit, is ranked 20 places lower, with a D-Lo 40 points less than Murray’s.

The short answer, then, is yes. It must be noted, though, that he isn’t the best choice among the big four to have a successful post-singles career as part of a team. That honor goes overwhelmingly to Rafael Nadal. Nadal’s career peak D-Lo is 100 points higher than Murray’s, and even his grass-court rating–based, admittedly, on some old results–is 70 points higher. Aside from the injured doubles wizard Jack Sock, Nadal is the best active player absent from the Wimbledon draw.

So, Murray/Nadal, Wimbledon 2021 champions? Sounds good to me–as long as Herbert relinquishes his new partner and finally commits to focusing on singles.

Let Bernie Keep His Money

Italian translation at settesei.it

On Tuesday, Bernard Tomic lost his first-round match at Wimbledon to Jo-Wilfried Tsonga. No surprise there: My forecast gave Tsonga a 64% chance of advancing, and that didn’t even take into account Tomic’s shaky health, which has caused him to retire from matches twice in the last six weeks.

Tomic-Tsonga immediately made the news, and for the wrong reasons. The Australian lost, winning only seven games. Ignominiously, the match lasted only 58 minutes, the shortest at Wimbledon since Roger Federer needed only 54 minutes to thump Alejandro Falla back in 2004.

The All England Club responded this morning, announcing that Tomic would lose his prize money. Officially, he “did not perform to the required professional standard.”

Fast and insufficiently furious

I don’t know whether Tomic performed to the required professional standard, because there’s no exact definition of “professional standard.” I suspect it’s some combination of the following:

  • The player lost badly
  • The player has a reputation for tanking
  • The match got a lot of attention so we have to be seen doing something about it

What I do know is that Wimbledon officials are looking at the wrong number. Yes, 58 minutes is an extremely fast three-set match. But Tomic–even when he’s fully engaged and playing his best–is probably the quickest player on tour, often serving as soon as a ballkid gets him the ball. Tsonga also plays fast. Neither player is a good returner, and the Frenchman is a devastating server on a fast surface, so the points were always going to be short.

The more appropriate metric, then, is points played. Tomic and Tsonga contested 125, which is considerably less headline-grabbing than the time on the clock.

Fines all around!

Suddenly, Tomic-Tsonga doesn’t stand out as much. Since 2000, there have been 77 other men’s grand slam matches that required 125 points or less. That’s almost exactly one per slam. The list includes two quarter-finals, three semi-finals, and the 2003 Australian Open title match, in which Andre Agassi dispatched Rainer Schuettler in 76 minutes, needing only 123 points. If we expand our view to matches with fewer than 130 points, we’re looking at another 45 matches, including both of this year’s Australian Open semi-finals.

Simply put: It is not unusual for a men’s slam match to be decided with 125 points. Really good players sometimes lose that fast. It just doesn’t usually attract so much attention, because on average, 125 points takes an hour and 21 minutes to play.

Of course, there are plenty of one-sided contests in the women’s draw, as well. 125 points is about 42 per set, so the “Tomic line” is at 83 or 84 points for a best-of-three match. Since 2003, there have been 235 women’s singles matches of 83 points or less, including five at this year’s French Open alone. (Ironically, Anna Tatishvili’s loss to Maria Sakkari, which triggered its own unprecedented fine, lasted 93 points and 28 minutes per set.)

Reactionary

All of this isn’t to say that Tomic tried his hardest on Tuesday, or that he “deserves” £45,000 in an ethical sense. If tournament referees made it a practice to review video of every first-round match and dock the prize money of the one player who competed most lackadaisically, then sure, the Australian is probably that guy at Wimbledon this year.

But that’s not how it works. The “professional standard” clause is almost never invoked. Had Tomic frittered away more time between points in order to push this match over the one-hour mark, or the offender had been a player with a less checkered past, we wouldn’t be talking about it now.

If the All England Club were focused on the right metric–the amount of tennis played, not how long it took–Bernie’s speedy, casual style of play wouldn’t be in the headlines. After all, there’s another casual, mercurial Australian with a poor return game who deserves more of our attention today.

Visualizing Trends in Net Play Across Five Decades of Grass Court Tennis

Earlier this week, I wrote about one aspect of the long-term decline in net play: the widespread belief that approaching the net is more difficult now because fewer players have a weaker side. I presented evidence indicating that most players still have a weaker side, which suggests that all groundstrokes–on both strong and weak sides–have gotten stronger, making net play a riskier proposition.

If that is true, it is reasonable to assume that passing shot winners are more frequent (relative to the number of net approaches), and perhaps that volleys are more aggressive, resulting in more first-volley winners and first-volley errors. More powerful and precise strokes should, on balance, make net points shorter than they used to be.

We can begin to test these theories using the extensive shot-by-shot records assembled by the Match Charting Project (MCP). MCP data includes every men’s Wimbledon final and semi-final back to 1990, as well as many elite-level grass court matches from the 1970s and 80s. For the purposes of today’s study, I will use only Wimbledon semi-finals and finals, plus a handful of other grass court matches from 1970-89 to complement the sparser Wimbledon data. This way, we know we’re comparing the elites of various generations to one another.

Contemporary net approaches

Let’s start by looking at what happens in a 2010s Wimbledon’s men’s final or semi-final when a player approaches the net. I’m excluding serve-and-volley points, and will do so throughout. I’m also excluding approach shot winners, which are often little more than gestures in the direction of the net following a big shot. (Even when they’re not, it can be difficult for charters to distinguish between approach and non-approach winners.) Thus, we’re looking at about 1,250 net approaches in which the other player got his racket on the ball.

The ball came back almost 73% of the time, and on slightly more than half the points, the approaching player put his first volley (or smash, or whatever shot he needed to hit) in play. 19% of the points saw a second passing shot attempt put in play, and nearly 12% had a second net shot keep the point going. About 1 in 30 approach-shot points continued even longer, forcing the the netman to contend with a third pass attempt.

The following visualization is a Sankey diagram showing how these net points developed. “App” stands for approach, “Unret” for “unreturned,” “Pass1” for “first passing shot,” “V1” for “first volley,” and so on. Mouse over any region of the diagram for a brief summary of what it represents.

2010s Wimbledon Net ApproachesApps → Pass1 In: 72.6%Pass1 In → V1 In: 51.2%V1 In → Unret V1: 32.1%Unret V1 → App’er Wins: 32.1%Apps → Unret App: 27.4%Unret App → App’er Wins: 27.4%Pass1 In → Unret Pass1: 21.4%Unret Pass1 → App’er Loses: 21.4%V1 In → Pass2 In: 19.1%Pass2 In → V2 In: 11.6%V2 In → Unret V2: 8.4%Unret V2 → App’er Wins: 8.4%Pass2 In → Unret Pass2: 7.5%Unret Pass2 → App’er Loses: 7.5%V2 In → Rally Continues: 3.2%Rally Continues → App’er Loses: 1.9%Rally Continues → App’er Wins: 1.3%Apps: 100%Apps: 100%Unret App: 27.4%Unret App: 27.4%Pass1 In: 72.6%Pass1 In: 72.6%V1 In: 51.2%V1 In: 51.2%Unret Pass1: 21.4%Unret Pass1: 21.4%Unret V1: 32.1%Unret V1: 32.1%Pass2 In: 19.1%Pass2 In: 19.1%V2 In: 11.6%V2 In: 11.6%Unret Pass2: 7.5%Unret Pass2: 7.5%Unret V2: 8.4%Unret V2: 8.4%Rally Continues: 3.2%Rally Continues: 3.2%App’er Wins: 69.2%App’er Wins: 69.2%App’er Loses: 30.8%App’er Loses: 30.8%

There’s a lot of information in the graphic, and it may not be entirely intuitive, especially hindered by my clunky design. Each region is sized based on what fraction of points developed in a certain way. As the regions move toward the right side of the diagram, they as classified by whether the approaching player won the point. As we can see, in the 2010s sample, these approach shots resulted in points won about 69% of the time.

The golden era

To compare eras, we need more than just one decade’s worth of data. I separated the approach shots by decade (grouping together the 70s and 80s), and the most distinctive era turned out to be the 1990s, when Pete Sampras ruled the roost and many of his challengers were equally aggressive.

Far more points were opened with a serve-and-volley: almost 81% in the 1990s compared to 7% in this decade. Even with the server claiming the net so early and so often, there were still many more non-serve-and-volley net approaches two decades ago. Then, there were about 85 “other” net approaches per match; this decade, there have been about 27. Thus, it is reasonable to assume that the typical net approach started from a less favorable position. These days, players only approach when the point has developed in a particularly inviting way.

Here is another diagram, this one showing what happened following 1990s net approaches:

1990s Wimbledon Net ApproachesApps → Pass1 In: 65.5%Pass1 In → V1 In: 44.4%Apps → Unret App: 34.5%Unret App → App’er Wins: 34.5%V1 In → Unret V1: 23.9%Unret V1 → App’er Wins: 23.9%Pass1 In → Unret Pass1: 21.1%Unret Pass1 → App’er Loses: 21.1%V1 In → Pass2 In: 20.5%Pass2 In → V2 In: 10.7%Pass2 In → Unret Pass2: 9.8%Unret Pass2 → App’er Loses: 9.8%V2 In → Unret V2: 7.8%Unret V2 → App’er Wins: 7.8%V2 In → Rally Continues: 2.9%Rally Continues → App’er Loses: 1.8%Rally Continues → App’er Wins: 1.1%Apps: 100%Apps: 100%Unret App: 34.5%Unret App: 34.5%Pass1 In: 65.5%Pass1 In: 65.5%V1 In: 44.4%V1 In: 44.4%Unret Pass1: 21.1%Unret Pass1: 21.1%Unret V1: 23.9%Unret V1: 23.9%Pass2 In: 20.5%Pass2 In: 20.5%V2 In: 10.7%V2 In: 10.7%Unret Pass2: 9.8%Unret Pass2: 9.8%Unret V2: 7.8%Unret V2: 7.8%Rally Continues: 2.9%Rally Continues: 2.9%App’er Wins: 67.3%App’er Wins: 67.3%App’er Loses: 32.7%App’er Loses: 32.7%

It’s striking to see that, back when net play was much more common, with a master such as Sampras dominating our sample, net approaches were less successful than they are today, resulting in a 67% win rate instead of 69%. However, it’s tough to know how today’s players–even a confident aggressor like Roger Federer or a volleying wizard like Rafael Nadal–would fare if they came forward four times as much. Assuming they pick their spots wisely, their success rate would be lower than 69%. The only question is how much lower.

Contrary to my inital hypothesis, passing shots seemed to be higher-risk and higher-reward in the 1990s than in the 2010s. Two decades ago, only 65.5% of initial passing shot attempts were put in play (compared to 72.6% today), though nearly as many of those attempts resulted in winners (21.1% to 21.4%). It was the volleyers who were either more conservative or less powerful in the 1990s. Then, barely half of first volleys ended the point in the netman’s favor; now, the number is closer to 60%. Again, this could be because today’s players pick their spots more carefully, allowing them to hit easier first volleys.

The early days

We’ve seen how net approaches developed in the 1990s and the 2010s. It would be reasonable to assume that the 1980s (with several late ’70s matches thrown in) were like the 1990s, but more so. Instead, the results are more of a mixed bag, with some characteristics that look like the ’90s, and others that are closer to today’s numbers.

Here is the diagram:

1980s Wimbledon Net ApproachesApps → Pass1 In: 70.4%Pass1 In → V1 In: 48.9%Apps → Unret App: 29.6%Unret App → App’er Wins: 29.6%V1 In → Pass2 In: 26.1%V1 In → Unret V1: 22.8%Unret V1 → App’er Wins: 22.8%Pass1 In → Unret Pass1: 21.5%Unret Pass1 → App’er Loses: 21.5%Pass2 In → V2 In: 15.6%V2 In → Unret V2: 10.8%Unret V2 → App’er Wins: 10.8%Pass2 In → Unret Pass2: 10.5%Unret Pass2 → App’er Loses: 10.5%V2 In → Rally Continues: 4.8%Rally Continues → App’er Loses: 2.8%Rally Continues → App’er Wins: 2%Apps: 100%Apps: 100%Unret App: 29.6%Unret App: 29.6%Pass1 In: 70.4%Pass1 In: 70.4%V1 In: 48.9%V1 In: 48.9%Unret Pass1: 21.5%Unret Pass1: 21.5%Unret V1: 22.8%Unret V1: 22.8%Pass2 In: 26.1%Pass2 In: 26.1%V2 In: 15.6%V2 In: 15.6%Unret Pass2: 10.5%Unret Pass2: 10.5%Unret V2: 10.8%Unret V2: 10.8%Rally Continues: 4.8%Rally Continues: 4.8%App’er Wins: 65.2%App’er Wins: 65.2%App’er Loses: 34.8%App’er Loses: 34.8%

In the 1980s, nearly as many passing shot attempts were put in play as they are today, in contrast to the lower rate during the 1990s. First volleys are a similar story. When passing shot attempts came back, approaching players put a volley (or other net shot) back in the court about 70% of the time–similar numbers in the 1980s and 2010s, but a couple percentage points higher than in the 1990s.

What is different is what happened next. In the 1980s, if the approaching player put his first volley back in play, it came back again 53% of the time. That rate is one of the few clear trends over time: It fell to 46% in the 1990s, 45% in the 2000s, and 37% in the 2010s. As a result, the ’80s saw far more second volleys and points that extended even further, compared to more recent eras. The lack of first-volley putaways meant that net approaches only converted into points won about 65% of the time.

A cautious narrative

There is no simple explanation that accounts for all of these numbers, because we are not seeing the direct result of a single factor, like the shift from wooden rackets or to more topspin-friendly string. Technological changes certainly have an impact, but as soon as the balance between approacher and opponent shifts, players adjust their strategy accordingly.

For instance, the rate of points won on net approaches appears to have steadily increased, from 65% in the 1980s to 67% in the 1990s to 69% today. The first rise could be attributed to racket technology, which gave aggressors more power and control. But the second rise came over a time period in which string technology offered more help to defenders. The higher rate of approach points won isn’t because players are better at it, it’s because they picked their spots more carefully.

What we might focus on instead, then, is how much these diagrams look alike, even though they represent vastly different eras. While there isn’t exactly a net-approach-strategy equilibrium that has held through the decades, player decision-making has kept these rates from varying too wildly. If passing shot winners start going up, we’ll probably see even fewer approaches–with the remaining approaches in still more favorable moments–or a continued increase in the percentage of approaches to the backhand side. That’s another clear trend over the last few decades, but it’s a topic for another day.

Rather than succumbing to nostalgia and bemoaning the decline of net play, it’s better to celebrate the adaptability of tennis players at the highest level. While the game a whole has become more defensive, backcourt denizens from Bjorn Borg (94 approaches per charted grass-court match) to Novak Djokovic (21 approaches per match) have reminded us that adjustments work in both directions. With parameters such as technology, surface, and opponent skills constantly changing, we can’t expect winning strategy to remain the same.

Thanks to SankeyMATIC for making it easy to create the diagrams.

Economist: Cori Gauff announces herself at Wimbledon

At the Economist’s Game Theory blog, I wrote about Cori Gauff’s historic upset of Venus Williams:

IT IS hard to avoid the impression that the tennis world has witnessed a changing of the guard. On July 1st , the opening day of the 2019 Championships at Wimbledon, Cori Gauff, a 15-year-old American prospect, upset the five-times champion Venus Williams in straight sets. Ms Williams, aged 39, was not the highest-ranked player to fall on the first day of the tournament; that honour belonged to the reigning US Open champion, Naomi Osaka, the second seed. But no first-round winner has garnered more attention than Ms Gauff, whose youth causes her to establish new records every time she steps on court.

Read the whole thing.

Podcast Episode 14: Wimbledon Preview

Episode 14 of the Tennis Abstract Podcast is Carl Bialik’s and my Wimbledon preview! We highlight the favorites, the overrated, and the underrated, along with a look at some of the most intriguing matchups. Along the way, we talk about the difficult of making grass court forecasts, and speculate about how players’ consistency changes with age.  Enjoy!

Click to listen, subscribe on iTunes, or use our feed to get updates on your favorite podcast software.

The Men Are Old, and The Best Men Are Even Older

Italian translation at settesei.it

It’s been one of the main talking points in men’s tennis for years now: The sport is getting older. Every year, a bigger slice of Grand Slam draws are taken up by thirty-somethings, and now, the entire big four has entered their fourth decades.

I don’t want to belabor the point. But my interest was piqued by an observation from commentator Chris Fowler this week:

When we talk about the sport getting older, this is what we really mean — the best guys are getting up in years.

When we calculate the average age of a draw, or the number of 30-somethings, we weight every player equally. Democratic as it is, it gives most of the weight to guys who are looking for flights home before middle Sunday. As substantial as the overall age shift has been over the last decade, the shift at the top of the game has been even more dramatic.

To quantify the shift, I calculated what I’ll call the “projected winner age” (PWA) of every Wimbledon men’s field from 1991 to 2017. This captures in one number the notion that Fowler is hinting at. We take a weighted average of all 128 men in the main draw, weighted by their chances of winning the tournament, as determined by grass-court Elos at the start of the event.

For example, last year’s Wimbledon men’s draw had an average age of 28.5 years, but a projected winner age of 30.0. We don’t yet know the exact average age of this year’s draw (it looks to be about the same, maybe a tiny bit younger), but we can already say that the PWA is 31.4.

An observer a decade ago would’ve thought such a number was insane. Here are the average ages and PWAs for the last 27 Wimbledons men’s events:

As recently as 2011, there wasn’t much difference between average age and PWA. Until 2015, the difference had never been greater than two years. Now, the difference is almost three years, and the point of comparison–average age–is nearly its own all-time high.

A lot of this, of course, is thanks to the big four. Even as the aging curve has shifted, allowing for late bloomers such as Stan Wawrinka, the biggest stars of the late ’00s–Roger Federer and Rafael Nadal–have declined even less than the revised aging curve would imply. In a sport hungry for new winners, we might have to settle for winners who are newly in their 30s.

Measuring the Impact of Wimbledon’s Seeding Formula

Italian translation at settesei.it

Unlike every other tournament on the tennis calendar, Wimbledon uses its own formula to determine seedings. The grass court Grand Slam grants seeds to the top 32 players in each tour’s rankings, and then re-orders them based on its own algorithm, which rewards players for their performance on grass over the last two seasons.

This year, the Wimbledon seeding formula has more impact on the men’s draw than usual. Seven-time champion Roger Federer is one of the best grass court players of all time, and though he dominated hard courts in the first half of 2017, he still sits outside the top four in the ATP rankings after missing the second half of 2016. Thanks to Wimbledon’s re-ordering of the seeds, Federer will switch places with ATP No. 3 Stan Wawrinka and take his place in the draw as the third seed.

Even with Wawrinka’s futility on grass and the shakiness of Andy Murray and Novak Djokovic, getting inside the top four has its benefits. If everyone lives up to their seed in the first four rounds (they won’t, but bear with me), the No. 5 seed will face a path to the title that requires beating three top-four players. Whichever top-four guy has No. 5 in his quarter would confront the same challenge, but the other three would have an easier time of it. Before players are placed in the draw, top-four seeds have a 75% chance of that easier path.

Let’s attach some numbers to these speculations. I’m interested in the draw implications of three different seeding methods: ATP rankings (as every other tournament uses), the Wimbledon method, and weighted grass-court Elo. As I described last week, weighted surface-specific Elo–averaging surface-specific Elo with overall Elo–is more predictive than ATP rankings, pure surface Elo, or overall Elo. What’s more, weighted grass-court Elo–let’s call it gElo–is about as predictive as its peers for hard and clay courts, even though we have less grass-court data to go on. In a tennis world populated only by analysts, seedings would be determined by something a lot more like gElo and a lot less like the ATP computer.

Since gElo ratings provide the best forecasts, we’ll use them to determine the effects of the different seeding formulas. Here is the current gElo top sixteen, through Halle and Queen’s Club:

1   Novak Djokovic         2296.5  
2   Andy Murray            2247.6  
3   Roger Federer          2246.8  
4   Rafael Nadal           2101.4  
5   Juan Martin Del Potro  2037.5  
6   Kei Nishikori          2035.9  
7   Milos Raonic           2029.4  
8   Jo Wilfried Tsonga     2020.2  
9   Alexander Zverev       2010.2  
10  Marin Cilic            1997.7  
11  Nick Kyrgios           1967.7  
12  Tomas Berdych          1967.0  
13  Gilles Muller          1958.2  
14  Richard Gasquet        1953.4  
15  Stanislas Wawrinka     1952.8  
16  Feliciano Lopez        1945.3

We might quibble with some these positions–the algorithm knows nothing about whatever is plaguing Djokovic, for one thing–but in general, gElo does a better job of reflecting surface-specific ability level than other systems.

The forecasts

Next, we build a hypothetical 128-player draw and run a whole bunch of simulations. I’ve used the top 128 in the ATP rankings, except for known withdrawals such as David Goffin and Pablo Carreno Busta, which doesn’t differ much from the list of guys who will ultimately make up the field. Then, for each seeding method, we randomly generate a hundred thousand draws, simulate those brackets, and tally up the winners.

Here are the ATP top ten, along with their chances of winning Wimbledon using the three different seeding methods:

Player              ATP     W%  Wimb     W%  gElo     W%  
Andy Murray           1  23.6%     1  24.3%     2  24.1%  
Rafael Nadal          2   6.1%     4   5.7%     4   5.5%  
Stanislas Wawrinka    3   0.8%     5   0.5%    15   0.4%  
Novak Djokovic        4  34.1%     2  35.4%     1  34.8%  
Roger Federer         5  21.1%     3  22.4%     3  22.4%  
Marin Cilic           6   1.3%     7   1.0%    10   1.0%  
Milos Raonic          7   2.0%     6   1.6%     7   1.7%  
Dominic Thiem         8   0.4%     8   0.3%    17   0.2%  
Kei Nishikori         9   1.9%     9   1.7%     6   1.9%  
Jo Wilfried Tsonga   10   1.6%    12   1.4%     8   1.5%

Again, gElo is probably too optimistic on Djokovic–at least the betting market thinks so–but the point here is the differences between systems. Federer gets a slight bump for entering the top four, and Wawrinka–who gElo really doesn’t like–loses a big chunk of his modest title hopes by falling out of the top four.

The seeding effect is a lot more dramatic if we look at semifinal odds instead of championship odds:

Player              ATP    SF%  Wimb    SF%  gElo    SF%  
Andy Murray           1  58.6%     1  64.1%     2  63.0%  
Rafael Nadal          2  34.4%     4  39.2%     4  38.1%  
Stanislas Wawrinka    3  13.2%     5   7.7%    15   6.1%  
Novak Djokovic        4  66.1%     2  71.1%     1  70.0%  
Roger Federer         5  49.6%     3  64.0%     3  63.2%  
Marin Cilic           6  13.6%     7  11.1%    10  10.3%  
Milos Raonic          7  17.3%     6  14.0%     7  15.2%  
Dominic Thiem         8   7.1%     8   5.4%    17   3.8%  
Kei Nishikori         9  15.5%     9  14.5%     6  15.7%  
Jo Wilfried Tsonga   10  14.0%    12  13.1%     8  14.0%

There’s a lot more movement here for the top players among the different seeding methods. Not only do Federer’s semifinal chances leap from 50% to 64% when he moves inside the top four, even Djokovic and Murray see a benefit because Federer is no longer a possible quarterfinal opponent. Once again, we see the biggest negative effect to Wawrinka: A top-four seed would’ve protected a player who just isn’t likely to get that far on grass.

Surprisingly, the traditional big four are almost the only players out of all 32 seeds to benefit from the Wimbledon algorithm. By removing the chance that Federer would be in, say, Murray’s quarter, the Wimbledon seedings make it a lot less likely that there will be a surprise semifinalist. Tomas Berdych’s semifinal chances improve modestly, from 8.0% to 8.4%, with his Wimbledon seed of No. 11 instead of his ATP ranking of No. 13, but the other 27 seeds have lower chances of reaching the semis than they would have if Wimbledon stopped meddling and used the official rankings.

That’s the unexpected side effect of getting rankings and seedings right: It reduces the chances of deep runs from unexpected sources. It’s similar to the impact of Grand Slams using 32 seeds instead of 16: By protecting the best (and next best, in the case of seeds 17 through 32) from each other, tournaments require that unseeded players work that much harder. Wimbledon’s algorithm took away some serious upset potential when it removed Wawrinka from the top four, but it made it more likely that we’ll see some blockbuster semifinals between the world’s best grass court players.

Nick Kyrgios and the First Fifty Matches

Italian translation at settesei.it

When Nick Kyrgios lost the Wimbledon quarterfinal to Milos Raonic yesterday, he was playing his 50th career match at the Challenger level or above. Round numbers invite big-picture analysis, so let’s see how Kyrgios stacks up to the competition at this early milestone.

When Monday’s rankings are released, Nick will debut in the top 100, all way up to #66. Only Rafael Nadal (61), Gael Monfils (65), and Lleyton Hewitt (65) have been ranked higher at the time of their 51th Challenger-or-higher match.  Roger Federer was #93, Novak Djokovic was #128, and Jo Wilfried Tsonga was #314. Of the current top 100, only ten players reached a double-digit ranking by their 51st match.

The wealth of ranking points available at Grand Slams have played a big part in Kyrgios’s rise, but they don’t tell the whole story. He has won 36 of his first 50 matches, equal to the best of today’s top 100. Nadal went 36-14, and next on the list is Djokovic and Santiago Giraldo (who played almost all Challengers) at 34-16. Most of Nick’s wins before this week came at Challengers, and he has won four titles at the level.

No other active player won four Challenger titles in his first 50 matches. Eight others, including Djokovic, Tsonga, Stanislas Wawrinka, and David Ferrer, won three. All of them needed more events at the level to win three titles than Kyrgios did to win four.

Nick’s short Challenger career is another indicator of a bright future. He has only played nine Challenger events, and with his ranking in the 60s, he may never have to play one again. As I’ve previously written, the best players tend to race through this level: Federer, Nadal, and Djokovic all played between eight and twelve Challengers. It’s a rare prospect that makes the jump in fewer than 20 events, and when I researched that post two years ago, more than half of the top 100 had played at least 50 Challengers.

One category in which the Australian doesn’t particularly stand out is age. When he plays his 51st match, he’ll a couple of months past his 19th birthday. Roughly one-quarter of the current top 100 reached that match total at an earlier age. Nadal, Richard Gasquet, and Juan Martin del Potro did so before their 18th birthday, while Djokovic, Hewitt, and Bernard Tomic needed only a few more weeks beyond that.

Without knowing how Kyrgios would’ve performed on tour a year or two earlier, it’s tough to draw any conclusions. His 36-14 record at 19 certainly isn’t as impressive as Rafa’s equivalent record at 17.

Cracking the top 100 at 17 or 18 is a much better predictor of future greatness than doing so at 19, but as the tour ages, 19 may be the new 16. Grigor Dimitrov didn’t enter the top 100 until he was three months short of his 20th birthday, while Dominic Thiem and Jiri Vesely were still outside the top 100 on their 20th birthdays. Among his immediate cohort, Kyrgios stands alone: No other teenager is ranked within the top 240.

As predictive measures go, Nick’s Wimbledon performance–built on his poise under pressure–is the best sign of them all. Only seven active players have reached a Grand Slam quarterfinal as a teenager, and four of them–Fed, Rafa, Novak, and Lleyton–went on to reach #1. (The other three are Delpo, Tomic, and Ernests Gulbis.)

For a player with only fifty matches under his belt, that’s excellent company.

Nick Kyrgios, Young Jedi of the Tiebreak

Italian translation at settesei.it

At Wimbledon this year, 19-year-old rising star Nick Kyrgios has shown himself to be impervious to pressure. In his second round upset of Richard Gasquet, he tied a Grand Slam record by surviving nine match points. Against Rafael Nadal, he withstood perhaps the best clutch player in the game. Despite Nadal’s stature as one of the best tiebreak players in the game, the Australian won both of the tiebreaks they contested.

As I’ve shown in other posts, tiebreaks are–for most players–toss-ups. Better players typically win more than 50% of the tiebreaks they play, but that’s because they’re better players, not because they have some tiebreak-specific skill. Only a very few men–Nadal, Roger Federer, and John Isner are virtually alone among active players–win even more tiebreaks than their non-tiebreak performance would indicate.

Kyrgios is making a very strong case that he should be added to the list. In his career at the ATP, ATP qualifying, and Challenger levels, he’s won 23 of 31 tiebreaks, good for an otherworldly 74% winning percentage. Isner has never posted a single-season mark that high, and Federer has only done so twice.

Nick isn’t playing these matches against weaker opponents, and he isn’t cleaning up in non-tiebreak sets. (Too many scores like 7-6 6-1 might suggest that he shouldn’t have gotten himself to 6-6 in the first place.) Based on Kyrgios’s serve and return points won throughout each match, a tennis-playing robot would have had a 52% chance of winning each tiebreak.

Given those numbers, it’s extremely likely that Kyrgios is one of the outliers, a player who wins many more tiebreaks than expected. There’s only a 1% chance that his excellent winning percentage is purely luck. We can be 95% sure that a tiebreak winning percentage of 58% or better is explained by skill, and 90% sure that his tiebreak skill deserves at least a winning percentage of 62%.

Either one of these more modest figures would still be excellent. Milos Raonic, his quarterfinal opponent and a player who represents an optimistic career path for Kyrgios’s next few years, has posted a 58% tiebreak winning percentage at tour level. Tomorrow’s match won’t be enough to prove which player is better in these high-pressure moments, but given each man’s playing style, it’s almost certain that we’ll see Kyrgios tested in another batch of tiebreaks.

Unbroken Grand Slam Quarterfinalists

Italian translation at settesei.it

Through the first four rounds at Wimbledon, Roger Federer‘s serve has not been broken. In that span, he has faced nine break points, including only four in his last three matches.

Since 1991–the first year for which match stats are available–this is only the 8th time a player reached the quarters of a men’s major without losing serve. Only Federer in 2004 and Ivo Karlovic in 2009 have done so at Wimbledon. Federer and Nadal are the only players to have done so more than once. (Fed was also unbroken through four matches in Melbourne last year, and Rafa accomplished the feat  at the 2010 and 2013 US Opens.)

Roger’s nine break points faced are a bit less impressive. More than 5% of the 752 Grand Slam quarterfinalists since 1991 have allowed fewer, including Federer himself on several occasions. He allowed only three break points at Wimbledon in 2007, and only four at three other majors.

Dominant as such a performance is, it’s less clear whether it has any predictive value. A major confounding factor is quality of competition–would anyone expect Paolo Lorenzi or Santiago Giraldo to break Federer on grass? While he built on these superb serving performances and went on to win the title at Wimbledon in 2004 and 2007, he failed to do so at the three majors when he allowed only four break points through this stage of the tournament.

Without accounting for player quality, there is a weak negative correlation between matches won at the event and break points (and breaks) allowed. (For instance, for matches won and break points allowed in the first four matches, r = -0.25. Excluding Roland Garros, r = -0.27.) In other words, if all you know about two players is how many break points they faced in the first four rounds, bet on the guy who faced fewer.

But it’s a weak relationship, and when player quality is taken into account, it vanishes to almost nothing. Eight of the 24 players who were broken one or fewer times in the first four rounds went on to win the title, but I suspect that has more to do with the prevalence of Rafa, Roger, and Pete Sampras–the best players are most likely to go unbroken, and the best players are most likely to go deepest at Slams.

When the best players struggle on serve in early rounds, it’s hardly a death knell for their title chances. Only four times in Fed’s 31 previous hard- and grass-court Slam quarterfinal runs has he been broken more than six times before the quarters, and he won the tournament one two of those four occasions. He’s surely happy to be into the quarterfinals this week with a minimum of fuss, but the fuss level only says so much about how happy he’ll be come Sunday.