Author: jsackmann

Harrison’s Luck, Karlovic’s Danger, and Vesely’s Prep

When Ryan Harrison drew Rafael Nadal in the first round of the US Open, the reaction in the twitterverse was instantaneous and unanimous. A guy with horrible luck in Grand Slam draws just saw his luck get even worse.

Certainly, drawing one of the big four (or big seven?) means an almost guaranteed early exit.  Harrison could’ve drawn a seed ranked much-lower, or better yet, one of the many anonymous characters required to fill up the 128-man field.

But has Ryan’s luck really been that bad?  In his previous twelve Slam appearances, Harrison has drawn a seed six times in the first time.  (An unseeded player has a one-in-three chance of pulling a seed, so he “should” have faced four seeds instead.)  Only one of those was a member of the big four–Andy Murray at the 2012 Australian–and two of them have been seeded 27th or worse.

The real complaint for Harrison’s supporters has been his second round draws.  In Melbourne this year and Wimbledon last year, he faced Novak Djokovic in the second round. One year ago in Flushing, his R64 opponent was Juan Martin del Potro.

Alright–that’s pretty bad luck.  But keep in mind that any unseeded player is very likely to face a seed in one of the first two rounds.  Harrison lucked into a slightly fortunate draw at Roland Garros this year, drawing Andrey Kuznetsov in the first then 19th-seeded John Isner in the second.

And of course, lucky or unlucky, there’s the question of whether Harrison is likely to beat anyone at a Grand Slam right now.  Ranked 97th, he’s one of the weakest players in the draw.  Given a luckier draw, there still wouldn’t be much hope that he would take advantage.

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Yesterday Ivo Karlovic qualified for the US Open main draw, and again the twitterverse responded unanimously.  To paraphrase everyone: “He’s a dangerous floater. No one wants to see him in the first round.”

I can’t speak to the psychological preferences of players, so maybe that’s right–maybe no one wants to see him in their section. But at this point in his career, there’s little reason to fear Dr. Ivo.

In fact, I wrote about this specific issue almost two years ago: “Karlovic has shown himself far less likely than the average player to perform above or below his ranking.”

Aside from a victory over Kevin Anderson in the thin air of Bogota and two wins by retirement, the highest-ranked player Karlovic has beaten in the last year was (then) #40 Grigor Dimitrov in Zagreb–indoors. He hasn’t scored a complete-match win against a top-20 player since he played Kei Nishikori in Davis Cup 18 months ago.

It’s true, Karlovic has a very good chance of advancing past James Blake in his first main draw match.  But that says more about the 33-year-old Blake than it does about Ivo.

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Diego Sebastian Schwartzman was so close to qualifying.  In yesterday’s final round, he took the first set from Albano Olivetti.  He saved a break in the third, went up a break for 4-2, but couldn’t close it out.

It would’ve been a remarkable achivement for the newly-minted 21-year-old.  He has built his ranking up to 131 entirely on the back of clay-court challengers.  In fact, he had played only eight career hard-court matches before this week, winning just two–both against fellow clay specialists in Melbourne qualifying this year.

For all that, Schwartzman would not have been the main draw contender with the least hard-court preparation this year!  That honor goes to Jiri Vesely, the 20-year-old Czech, who has not played a hard-court match since the Sarajevo (ice-rink) Challenger in March.

These two youngters’ routes to success reveal an interesting quirk of the ATP schedule.  While clay-court events are a distinct minority at tour level, they make up a slight majority among Challengers.  Furthermore, it is easier to fill out a minor-league schedule with clay events because of the dearth of hard-court options in April and May.  For instance, in the ten-week span this year from 22 April to 1 July, there were only four hard-court challengers–in Johannesburg, Kun-Ming, Karshi, and Busan.

For his part, Vesely has had an outstanding season.  In March, he was ranked outside the top 200.  After three Challenger titles (and two more finals, with losses to Radek Stepanek and Florian Mayer), he sits comfortably inside the top 100, with no need to qualify in New York.

Despite his scheduling choices, Vesely isn’t hopeless on hard courts.  Two years ago, he reached the final in the US Open junior tournament and won in Melbourne.

For his first match on the surface in months, the youngster got a manageable first-round opponent in Denis Kudla.  The winner of that battle of counterpunching youngsters will likely go no further, thanks to a second-round date with Tomas Berdych.

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Finally, my draw forecasts are up for both singles main draws. Men are here, and women are here.  With a little luck, they’ll update hourly throughout the tournament.

Five First-Round Men’s Qualifying Matches to Watch at the US Open

Why wait until next week to get excited about the US Open?  Qualifying rounds start tomorrow, and there is a ton of action all over the grounds as 128 men and 128 women fight for 16 spots in each main draw.  There’s more cash on the line than ever, so you can count on some very hard-fought contests for the right to stick around into next week.

1. Ivo Karlovic vs Mackenzie McDonald

You know Ivo.  Two weeks ago, you almost certainly didn’t know McDonald.  The UCLA commit’s pedestrian junior career didn’t prepare anyone for his victories over Nicolas Mahut and Steve Johnson in Cincinnati qualifying last week.  That’s right: The unranked 18-year-old made the main draw of last week’s Masters 1000 event, and the cannon-serving veteran did not.

I saw much of McDonald’s match against Johnson.  To the extent you can be a believer in a pint-sized player without any weapons, count me in.  He fought Johnson hard on every point, waiting until the older player made a mistake. That won’t work against most tour-level players, but it might do the trick against the Croatian.

They are third up on Court 11 today.

2. Jesse Huta Galung vs Florent Serra

Two years ago, Huta Galung qualified in Flushing and took a set from James Blake in the first round of main draw play.  It was something of a career highlight for the Dutchman, who has only won four main draw matches in his tour-level career.

Yet this year, he returns to New York on a tear.  He has a 29-7 record in Challengers this year, including wins in Cherbourg (as a 346th-ranked lucky loser), St. Brieuc, Scheveningen, and Tampere, along with a final in Meerbusch last week.  He broke into the top 100 for the first time with this week’s rankings, and he has almost no points to defend until Cherbourg comes along again at the end of next February.

I’ve long loved Huta Galung’s game–he’s a stylish player with plenty of variety who can move particularly well.  Even in a losing effort, he is enjoyable to watch.

His opener would have been on this list regardless of opponent, but Serra has the ability to turn this into one of the better matches of qualifying week–certainly one of the tougher tilts in the first round.  The 32-year-old is unlikely to recover the form that took him into the top 40 seven years ago, but remains a threat at the challenger level.

Look for this match on Wednesday’s schedule.

3. Evgeny Korolev vs Illya Marchenko

In contrast to the previous match, stylishness isn’t the word that comes to mind here.  Korolev is not just a slugger; he’s a ball-basher who has lost his way.  He broke into the top 100 as an 18-year-old, peaking inside the top 50, and had a double-digit ranking as recently as three years ago.  At the age of 25, he should be heading toward a new peak, but instead is languishing in Challengers, losing to … well, just about everybody.

Injuries have repeatedly derailed his progress, and since he has retired in two of his last three matches, it wouldn’t shock anyone if he didn’t complete this match, either.  But on a good day, he has an uncanny ability to smack groundstrokes to within inches of the baseline.  Though it it’s never pretty, I’m always impressed.

Marchenko has a more well-rounded game, and despite never cracking the top 60, has the physical potential to return to that range.  His qualifying match against Christian Harrison in Washington a few weeks ago was one of the better displays I saw at that event.  But it was typical Illya.  He was the superior player, except on crucial points.  Marchenko’s last six losses have been three-setters, yet only against Harrison did he push the final set past 6-4.

These guys play third on Court 4 today.

4. Cedrik Marcel Stebe vs Malek Jaziri

(Hey, it’s my list. If you don’t like my choices, make your own list!)

Stebe dominated the 2011 Challenger tour, then kept his ranking just high enough throughout 2012 to earn a direct entry into last year’s US Open, where he beat Viktor Troicki in the first round.  Two weeks later he beat Lleyton Hewitt in Davis Cup, and it’s been all downhill from there.  Aside from the final at the Tallahassee Challenger in the spring, there’s little sign of the guy who charged into the top 100 barely out of his teens.

The 22-year-old lefty is too passive to have a natural home on hard courts, though he has registered some big wins on the surface, such as the ’11 Challenger Tour finals and that Troicki upset.  That makes Jaziri an ideal opponent for him.  The 29-year-old Tunisian has played a bit more on hard courts this summer, showing up at a couple of North American challengers and playing qualifying in Washington, but he’s a counterpunching dirtballer at heart.

It could make for some ugly tennis, or it could generate some entertaining scampering around the back of the court.  They’ll play tomorrow.

5. Mitchell Krueger vs Lucas Pouille

It wouldn’t be a qualifying preview without some of the youngest players in the draw.  With so many of the fringey Americans wildcarded into the main draw, US fans need to look deeper for local boys, and Krueger is a good place to start.  The 19-year-old had a single ranking point when he got a qualifying wild card last year (and won a round); he has now edged into the top 500.  While he hasn’t made a strong impression on his first trip around the North American Challenger circuit, he has scored two top-300 wins.

Pouille, also 19, is a bit more advanced, having won 10 matches at the Challenger level and above since the beginning of this year.  Many view him as a big part of the future of French tennis, and with a ranking on the cusp of the top 200, he should be heavily favored here.

But the outcome isn’t what matters here; neither player is likely to reach the main draw.  In a qualifying field full of guys 10 years older, these two are unquestionably on the way up.  They’ll be on the Wednesday schedule.

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A few notes:

Toward Atomic Statistics

Italian translation at settesei.it

The other day, Roger Federer mentioned in a press conference that he’s “never been a big stat guy.”  And why would he be?  Television commentators and the reporters asking him post-match questions tend to harp on the same big-picture numbers, like break points converted and 2nd-serve points won.

In other words, statistics that look better when you’re winning points.  How’s that for cutting edge insight: You get better results when you win more points.  If I were in Fed’s position, I wouldn’t be a “big stat guy” either.

To the extent statistics have the potential to tell us about a particular player’s performance, we need to look at numbers that each player can control as much as possible.  Ace counts–though they are affected by returners to a limited extent–are an example of one of the few commonly-tracked stats that directly reflect an aspect of a player’s performance.  You can have a big serving day with not too many aces and a mediocre serving day with more, but for the most part, lots of aces means you’re serving well.  Lots of double faults means you’re not.

By contrast, think about points won on second serve, a favorite among the commentariat.  That statistic may weakly track second serve quality, but it also factors the returner’s second serve returns, as well as both player’s performance in rallies that begin close to an even keel.  It provides fodder for discussion, but it certainly doesn’t offer anything actionable for a player, or an explanation of exactly what either player did well in the match.

Atomic statistics

Aces and double faults are a decent proxy for performance on serve.  (It would be nice to have unreturnables as well, since they have more in common with aces than they do with serves that are returned, however poorly.)

But what about every other shot?  What about specific strategies?

An obvious example of a base-level stat we should be counting is service return depth.  Yes, it’s affected by how well the opponent serves, but it refers to a single shot type, and one upon which the outcome of a match can hinge.  It can be clearly defined, and it’s actionable.  Fail to get a reasonable percentage of service returns past the service line, and a good player will beat you.  Put a majority of service returns in the backmost quarter of the court, and you’re neutralizing much of the server’s advantage.

Here are more atomic statistics with the same type of potential:

  • Percentage of service returns chipped or sliced.
  • Percentage of backhands chipped or sliced.
  • Serves (and other errors) into the net, as opposed to other types of errors.
  • Variety of direction on each shot, e.g. backhands down the line compared to backhands crosscourt and down the middle.
  • Net approaches
  • Drop shot success rate (off of each wing).

Two commonly-counted statistics, unforced errors and winners, have many characteristics in common with these atomic stats, but are insufficiently specific.  Sure, knowing a player’s winner/ufe rate for a match is some indication of how well he or she played, but what’s the takeaway? Federer needs to be less sloppy? He needs to hit more winners?  Once again, it’s easy to see why players aren’t clamoring to hear these numbers.  No baseball pitcher benefits from learning he should give up fewer runs, or a hockey goaltender that he needs to allow fewer goals.

Glimmers of hope

With full access to Hawkeye data, this sort of analysis (and much, much more) is within reach.  Even if Hawkeye material remains mostly impenetrable, the recent announcement from SAP and the WTA holds out hope for more granular tennis data.

In the meantime, we’ll have to count this stuff ourselves.

Raonic, del Potro, and the Importance of One Point

In last night’s Coupe Rogers match between Milos Raonic and Juan Martin del Potro, one point stands out from the rest.

Raonic won the first set, then Delpo broke early in the second.  With del Potro serving at 4-3, Raonic earned a break point with a winner at the net.  Replays clearly show that he touched the net.  Had the chair umpire seen it in real time, Delpo would have been awarded the point.

The Argentine never recovered, losing the next nine points and the match.

The net touch, and the point Milos didn’t deserve, was clearly a turning point in the match.  But how important was it, really?

If we assume that the two men were equal and that both players win 75% of service points (not true in Delpo’s case yesterday, but reasonable for two big servers on hard courts), here is a summary of Raonic’s probability of winning at various stages of the match:

  • After winning the first set: 75.0%
  • With Delpo serving 4-3, 00-00: 52.4%
  • With Delpo serving 4-3, 40-40: 53.9%
  • After winning the “touch” point: 58.9%
  • If Delpo had won that point: 51.8%
  • After winning the “touch” game: 75.0%
  • After holding serve for 5-4: 76.3%

The controversial point was, clearly, very important.  The difference between winning it and losing it was 7%, a magnitude that doesn’t happen very often in a tennis match, especially outside of tiebreaks.

But the real story here is the next point.  Remember that under normal circumstances, del Potro is a huge server and Raonic does not have a strong return of serve.  (I say “normal circumstances” because somehow, Raonic won 50% of return points in this match.)

If a server is winning 75% of points on his own racquet, his probability of winning a game from break point down is still 67.5%.  There’s a 25% chance he’ll lose the game on the next point, of course, but a 75% chance he’ll get back to deuce, where his serve gives him a 90% chance of winning the game.

The touch point increased Raonic’s chances of winning from 53.9% to 58.9%.  The next point upped his odds from 58.9% to 75.0%.  Which one do you think was more important?

Another way of looking at this to consider what would’ve happened had there been no video replay, and no chance of del Potro spotting the touch and arguing with the umpire about it.  Normal Delpo would’ve stepped back to the line and hit a service winner.  Five minutes later he would’ve held serve again and the two men would’ve played a third set.

It’s easy to look back at this match and conclude that the net touch was the difference in the match.  But no: It was the reaction to the touch–the controversy itself–that had a much greater impact.

Help make TennisAbstract.com better (and promote your blog)

Today I’m launching a new project on TennisAbstract.com: links to great player news and analysis elsewhere on the web.

I hope you’ll work with me to make this a reality. Getting your blog posts and articles on TennisAbstract.com player pages is easy.

Step one: Fill out a quick form to tell me a few things about your site.

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Please read through the rest of this page. Then, if I haven’t scared you away, please submit your information.

How it works

Once every hour or so, I’ll check your RSS feed for new content and scan any new posts for TA player links. If you’re writing about Roger Federer and include a link to his TA page, your post will show up in the “Player News and Views” section of Federer’s page.

your links here

For now, each player page will show the most recent five posts. After approximately 30 days, I’ll drop each post from the database.

Finally, this is very much a work in progress, and I’m sure I’ll do some tweaking throughout the month of August. I’ll probably break stuff. Please let me know if you think things are not working like they should, but please also be patient.

The rules

There are, of course, some basic guidelines you’ll need to follow.

The object of including “News and Analysis” on TennisAbstract.com is just that: to provide news, views, and analysis. I’m not interested in including links to sites that simply list orders of play, match results, betting lines, or betting results.

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Finally–and this should be obvious–work must be your own. I won’t link to aggregators or any other kind of site that is recycling content that originates elsewhere.

I’m a reasonable guy, but I do retain the sole right to determine what sites and posts are included in this system. If you violate any of the above policies, or if you do other objectionable stuff that I didn’t think of until I catch you doing it, I’ll remove your site from the program and add several bad losses to your favorite player’s record.

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John Isner’s Momentary Tiebreak Blip

Tiebreak legend John Isner has now lost four tiebreaks in a row, including a demoralizing two breakers in his match yesterday against 71st-ranked Vasek Pospisil.  Aside from his loss to the Canadian, however, Isner’s sudden tiebreak weakness hasn’t hurt him, nor does it seem to be a sign of poor play or weak nerves.  In fact, he has excelled–as usual–on the North American hardcourts. Twice last week, against both Marcos Baghdatis and Dmitry Tursunov, Isner dropped the first set in a breaker, then came back to win the following two sets with scores of 6-4 or better.

Further, this brief spell of Haase-style tiebreak play follows a much longer stretch of typical end-of-set dominance.  Until losing the first set against Kevin Anderson in the Atlanta final, Isner had won 12 breakers in a row. He immediately bounced back from the setback against Anderson by winning two breakers to claim the match, then won two more in his next match against Alex Kuznetsov.

Summary: The tiebreak mojo is still intact.

At a broader level, Isner has won 70% of his tiebreaks over the last 52 weeks, a rate higher than he has ever sustained for a full season.  Specifically in 2013, he has won 28 of 39 tiebreaks, good for 72%.  By comparison, Anderson has won 57% this season, Roger Federer 59%, and even the inimitable Steve Darcis has never won more than 72% of breakers for a full year.

This isn’t to take away from Pospisil’s achievement, however.  Isner’s career tour-level tiebreak record of 65% suggests that taking two breakers from him in a single match is difficult, and it’s all the more so for a player who most would not consider as Big John’s equal.  In 25 career tour-level tiebreaks before yesterday’s match, the Canadian had won a mere 11.

In fact, of Isner’s 258 career best-of-three-set matches on tour, this was only the seventh in which he lost two sets 7-6.  Given the sheer number of tiebreaks he plays, that in itself quite the accomplishment.  No one had administered such a loss to Isner since last year’s Madrid Masters, where Marin Cilic beat him 7-6 7-6.

When watching the American lose the occasional tiebreak, it’s important to remember that for the vast majority of players, breaker outcomes are essentially luck.  Isner is one of the few players to demonstrate a consistent tiebreak skill, but even that skill can’t prevent the occasional serving outage or an outstanding run of play from a streaky opponent.

With Isner (and by extension, all US men) falling out of the top 20, it’s tempting to point fingers and look for answers.  But don’t blame Big John.  If you must find fault, blame Canada.

Rules for Records

Every tennis record comes with an asterisk.

What we’re mainly interested in are achievements at the top level of the men’s or women’s game.  I often use the term “tour-level” as shorthand for this, kind of like saying “Major Leagues” for baseball to cover the American League, National League, and a handful of long-ago defunct organizations.  It disguises unnecessary complexity and allows to get to the point.

For men’s tennis, “tour-level” generally means all ATP events, plus grand slams, plus Davis Cup.  Excluded are challengers, futures, and qualifying at all levels.  Usually we limit consideration to the professional era, though if we’re talking only about Slams, there’s no artificial start date.

Which Davis Cup matches? Grigor Dimitrov is 16-9 this year, but two of those wins were in Davis Cup Group 2 against Finns outside of the top 900.  Should we exclude Group 2?  (The ATP does.) How about Group 1? (The ATP doesn’t.)  How about any rubber when the opponent is outside the top 200?

And therein lies a major problem, and one that is not limited to records and streaks.  The level of a tennis match is not defined by the ranking points on offer; its difficulty is determined by the quality of the opponent.  In the middle of Robin Haase’s 15-month streak of lost tour-level tiebreaks, the Dutchman did win a breaker, in Rome qualifying against 81st-ranked Sergiy Stakhovsky.  It doesn’t “count.”  But a main-draw match one month later against 640th-ranked Mate Pavic does.

There’s no good solution.  It isn’t a matter of tennis’s “analytics problem,” it is a reflection of the structure of the sport.

If Surfaces are Converging…

Internet discussion has perked up about a post of mine from last month, The Mirage of Surface Speed Convergence.

Many people don’t like my results, and plenty of people just don’t like having someone challenge their preconceived notions–or those of the players they idolize.

Yet for all the chatter, no one has even attempted to address the question at the end of that post:

If surfaces are converging, why is there a bigger difference in aces now than there was 10, 15, or 20 years ago? Why don’t we see hard-court break rates getting any closer to clay-court break rates?

Unless there is a valid answer to those questions, it really doesn’t matter how you felt after watching the Miami final, or what a top player said in some press conference.

Barcelona or Bucharest? Scheduling Decisions Under the Microscope

This post has been withdrawn due to a mistake in the calculations that seriously affects its conclusions.  I am leaving this note here to avoid breaking the link.  Look on the bright side–on this site, there’s plenty of tennis analysis in which the mistakes have less serious effects.

Avoiding Double Faults When It Matters

Italian translation at settesei.it

The more gut-wrenching the moment, the more likely it is to stick in memory.  We easily recall our favorite player double-faulting away an important game; we quickly forget the double fault at 30-0 in the middle of the previous set.  Which one is more common? The mega-choke or the irrelevancy?

There are three main factors that contribute to double faults:

  1. Aggressiveness on second serve. Go for too much, you’ll hit more double faults.  Go for too little, your opponent will hit better returns.
  2. Weakness under pressure. If you miss this one, you lose the point. The bigger the point, the more pressure to deliver.
  3. Chance. No server is perfect, and every once in a while, a second serve will go wrong for no good reason.  (Also, wind shifts, distractions, broken strings, and so on.)

In this post, I’ll introduce a method to help us measure how much each of those factors influences double faults on the ATP tour. We’ll soon have some answers.

In-game volatility

At 30-40, there’s more at stake than at 0-0 or 30-0.  If you believe double faults are largely a function of server weakness under pressure, you would expect more double faults at 30-40 than at lower-pressure moments.  To properly address the question, we need to attach some numbers to the concepts of “high pressure” and “low pressure.”

That’s where volatility comes in.  It quantifies how much a point matters by considering several win probabilities.  An average server on the ATP tour starts a game with an 81.2% chance of holding serve.  If he wins the first point, his chances of winning the game increase to 89.4%. If he loses, the odds fall to 66.7%.  The volatility of that first point is defined as the difference between those two outcomes: 89.4% – 66.7% = 22.7%.

(Of course, any number of things can tweak the odds. A big server, a fast surface, or a crappy returner will increase the hold percentages. These are all averages.)

The least volatile point is 40-0, when the volatility is 3.1%. If the server wins, he wins the game (after which, his probability of winning the game is, well, 100%). If he loses, he falls to 40-15, where the heavy server bias of the men’s game means he still has a 96.9% chance of holding serve.

The most volatile point is 30-40 (or ad-out, which is logically equivalent), when the volatility is 76.0%.  If the server wins, he gets back to deuce, which is strongly in his favor. If he loses, he’s been broken.

Mixing in double faults

Using point-by-point data from 2012 Grand Slam tournaments, we can group double faults by game score.  At 40-0, the server double faulted 3.0% of points; at 30-0, 4.2%; at ad-out, 2.8%.

At any of the nine least volatile scores, servers double faulted 3.0% of points. At the nine most volatile scores, the rate was only 2.7%.

(At the end of this post, you can find more complete results.)

To be a little more sophisticated about it, we can measure the correlation between double-fault rate and volatility.  The relationship is obviously negative, with an r-squared of .367.  Given the relative rarity of double faults and the possibility that a player will simply lose concentration for a moment at any time, that’s a reasonably meaningful relationship.

And in fact, we can do better.  Scores like 30-0 and 40-0 are dominated by better servers, while weaker servers are more likely to end up at 30-40. To control for the slightly different populations, we can use “adjusted double faults” by estimating how many DFs we’d expect from these different populations.  For instance, we find that at 30-0, servers double fault 26.7% more than their season average, while at 30-40, they double fault 28.6% less than average.

Running the numbers with adjusted double fault rate instead of actual double faults, we get an r-squared of .444.  To a moderate extent, servers limit their double faults as the pressure builds against them.

More pressure on pressure

At any pivotal moment, one where a single point could decide the game, set, or match, servers double fault less than their seasonal average.  On break point, 19.1% less than average. With set point on their racket, 22.2% less. Facing set point, a whopping 45.2% less.

The numbers are equally dramatic on match point, though the limited sample means we can only read so much into them.  On match point, servers double faulted only 4 times in 296 opportunities (1.4%), while facing match point, they double faulted only 4 times in 191 chances (2.2%).

Better concentration or just backing off?

By now, it’s clear that double faults are less frequent on important points.  Idle psychologizing might lead us to conclude that players lose concentration on unimportant points, leading to double faults at 40-0. Or that they buckle down and focus on the big points.

While there is surely some truth in the psychologizing–after all, Ernests Gulbis is in our sample–it is more likely that players manage their double fault rates by changing their second-serve approach.  With a better than 9-in-10 chance of winning a game, why carefully spin it in when you can hit a flashy topspin gem into the corner?  At break point, there’s no thought of gems, just fighting on to play another point.

And here, the numbers back us up, at least a little bit.  If players are avoiding double faults by hitting more conservative second serves on important points, we would expect them to lose a few more second serve points when the serve lands in play.

It’s a weak relationship, but at least the data suggests that it points in the expected direction.  The correlation between in-game volatility and percentage of second serve points won is negative (r = -0.282, r-squared = 0.08).  Complicating the results may be the returner’s conservative approach on such points, when his initial goal is simply to keep the ball in play, as well.

Clearly, chance plays a substantial role in double faults, as we expected from the beginning.  It’s also clear that there’s more to it.  Some players do succumb to the pressure and double fault some of the time, but those moments represent the minority.  Servers demonstrate the ability to limit double faults, and do so as the importance of the point increases.

Continue reading Avoiding Double Faults When It Matters