Sao Paulo Challenger: Day Two

In Sao Paulo, Tuesday brought the second half of first-round singles, a scattering of interesting doubles matches, and inexplicable swarms of gnats.  The gnats were almost as aggravating as the singles matches.

Click here for my reports on day one matches.

Renzo Olivo (ARG) vs Julio Cesar Campozano (ECU)

The question of the day was, “Who knows how to play tennis on hard courts?”  The answers were not encouraging.

Olivo is one of only 18 players under the age of 21 inside the ATP top 300, and it only takes a few minutes to realize he got there based on clay-court results.  That’s the generous assumption, anyway, since he looked simply dreadful.

His groundstrokes and movement looked as if somehow told him to try playing closer to the baseline, and he was trying it for the first time.  He missed easy forehands in every direction, often misjudging the bounce.  As the situation grew increasingly bleak (he ultimately lost the match 6-2 6-0), he went for more and more drop shot/lob combinations.  This was particularly painful since he missed most of the drop shots and then, when he made one, managed to miss the lob.

Perhaps Olivo is a future star, but that future isn’t any time soon.

Campozano isn’t a future star either–he’ll turn 27 later this month and has yet to crack the top 200–but he looked much more comfortable on the surface.  In fact, he looked like a good doubles player trying his hand at singles, with a consistent, well-placed serve and aggressive, compact groundstrokes.  His movement to the backhand was particularly impressive.

Perhaps Campozano’s most notable achievement in this first-round match was to stay steady through Olivo’s barrage of random unforced errors.  A lesser players would have let his level slip after an easy 6-2 first set; the Ecuadorian simply kept up the same style, letting Olivo lose the second set the same way he lost the first.

Devin Britton (USA) vs Jorge Aguilar (COL)

This was the strangest match I saw at the tournament.  If such a thing is possible, Aguilar looked worse than Olivo.  Sure, Aguilar has much more experience on clay, but he has a winning record in challenger-level hard court matches.  Whether it was the beginning of the season or Britton’s game, the Colombian never found a rhythm.

For the American, let’s start with the positive.  Throughout the match, he served wonderfully, utilizing the slice out wide in the deuce court repeatedly, especially once he learned Aguilar was never going to get it back.

Beyond that, however, I don’t see the weapons that will make Britton a future top player.  Even his serve, well-placed as it was, didn’t look like a first-class weapon.  In build and game plan, he’s a bit like Sam Querrey, but without nearly as much power.  When it came time to get aggressive on the ground, he seemed even less sure of himself than some of the awkward clay-courters in the draw.  While I wasn’t able to watch the entire match (Olivo-Campozano started at the same time), I’m not sure I saw a single clean forehand winner from Britton.  To succeed, his game will need to be built around quick points that end that way, so that’s an enormous gap.

As far as Aguilar is concerned, the less said, the better.

Austin Krajicek (USA) vs Horacio Zeballos (ARG)

As noted yesterday, I’m not impressed by Krajicek’s game.  But his performance against the #1 seed (and the only top-100 player in the draw) gave me some reasons to reevaluate my opinion.

Even when every player in the draw is within a fairly narrow range of about #100 to #400 in the world, it’s remarkable how much the better players stand out.  Zeballos is in a class by himself, especially in the way he moves around the court.  He simply makes the game look easier than anyone else at this event.  And for all that, he barely squeaked past the American.

Against a better player than the day before, Krajicek’s forehand was a bigger weapon, even if he doesn’t yet have the tactical sense or net game to follow up some opportunities.  Most impressive, though, was his mental steadiness at a time when many–far superior–players would have wilted.

At 2-2 in the second set tiebreak, Zeballos hit an “ace” that dribbled off the net cord.  Krajicek had fought hard just to get to that tiebreak, and now luck turned against him.  On the next point, he hit an ace to even the score.  Then, after a couple of clunky points, he hit two more aces to save the first two match points at 6-3.  It wasn’t good enough, as Zeballos took the breaker 7-5, but it made for a good showing against a very talented top-100 player.

Guido Andreozzi (ARG) vs Rafael Camilo (BRA)

Two years ago, Camilo reached the finals of this event as a qualifier.  In this, his first match returning from an injury that kept him off tour for nearly 15 months, he showed no signs of the talent required to reach those heights.

Camilo has much in common with Adam Kellner, not even close to an appropriate fitness level for a pro tennis player, relying on one or two big (erratic) weapons to win points.  The Brazilian did collect his share of cheap points off the serve.  When forced to hit a second shot (or, heaven forbid, return a serve), the ball was more likely to end up in the hands of a fan than a ballboy.

As for Andreozzi, it was difficult to evaluate a player who was able to sit back and watch his opponent lose the match.  The Argentine’s motions are bit unorthodox–his forehand reminds me of Marsel Ilhan‘s, if not quite that unusual–and he wasn’t quite comfortable with the surface.  He also seemed a bit overwhelmed by the power of Camilo’s serve.

There must be more to Andreozzi, as he’s reached the top 200 at age 21, and is playing a tight quarterfinal match with Zeballos as I write this.  Alas, he didn’t have to play much tennis to reach the second round.

Assorted doubles notes

Simon Stadler and Rameez Junaid squeaked by Facundo Bagnis and Alejandro Gonzalez.  Junaid, who I’m embarrassed to admit I had never even heard of, is now a full-time doubles specialist, and appears to have the skills to reach the next level.  Stadler seemed less sure of himself on the doubles court, while Junaid took control of the net like a pro.

Rik De Voest, the record-holder for most career challenger doubles titles, was in action with Marcelo Demoliner, against Marco Trungelliti and Ariel Behar.  It was a rather mediocre match, with few entertaining points and a fair bit of sloppy play.  But what caught my eye was De Voest’s absolutely relentless efforts to keep his partner in the right frame of mind.  The veteran South African was joking and smiling throughout the entire match, redoubling (ahem) his efforts whenever Demoliner seemed the least bit frustrated.  De Voest and Demoliner ended  up losing in the second round to Britton and Krajicek, but I’ll bet they were smiling until the end.

Finally, the day ended with the top-ranked doubles team of James Cerretani and Adil Shamasdin against the Brazilians Julio Silva and Thiago Alves.  In this case, it was the Brazilians joking around and the North Americans showing intensity.  In fact, Cerretani may be the most intense player I have ever seen on a tennis court.  A few ballboys from that match are probably still suffering nightmares in which they simply can’t find his towel.

More relevant to the outcome of the match, Cerretani and Shamasdin were by far the most professional doubles team in the draw.  They moved forward like the Bryans, at the slightest opportunity and as an imposing unit.  Both–and especially Cerretani–are absolute magicians at net, making for several entertaining points against the loose and talented Brazilians.

The bad news for the North Americans is that apart from doubles tactics and net play, they don’t have much to fall back on.  Even accounting for the precision required from doubles groundstrokes, their unforced error rates from the baseline were outrageous.  Neither had a particularly strong serve, and Shamasdin mixed in too many double faults for comfort.  It’s perhaps indicative of their general level that, despite looking like the far superior team, they needed a match tiebreak to win–and in the tiebreak, the lost the first four match points at 9-3.

More on the rule changes

Despite the occasional lucky point, like Zeballos’s ace against Krajicek, the players seem completely unfazed by playing service lets.  It eliminates arguments, speeds up the game, and doesn’t strongly favor any particular kind of player.  I’m afraid the traditionalists may win this round and prevent wider use of no-let service rules, but I’m convinced the sport will be better off as soon as we get rid of lets altogether.

The 25-second warning is a different issue altogether.  It sounds fine on paper, giving chair umpires a way to draw attention to a player’s slow pace without immediately affecting the course of the match.  But in practice, it simply opens more doors to pointless arguments–that, incidentally, slow down the game.

On Tuesday, umpires gave time warnings to two players, Andreozzi and Cerretani.  Andreozzi hadn’t been playing particularly slowly, and he certainly wasn’t gaining any advantage from it.  When the warning was called, it took another minute for the player to talk it out with the umpire.  In the second set of an otherwise brisk, lopsided match, it was unnecessary and bizarre.

Cerretani’s warning came near the business end of the match and raised more difficult issues.  Cerretani and Shamasdin play at a very deliberate pace, and while it didn’t occur to me to clock them between points, there’s no doubt they were regularly exceeding 25 seconds.  Cerretani, in particular, asked for the towel after nearly every point, and the ballboys weren’t very quick about it.  That, in fact, was his complaint to the umpire when the warning was called–that the ballboy was slow.

More troubling, though, is that the umpire seemed to call that warning at the immediate behest of the opposing team.  I didn’t understand the Portuguese, but it seemed as if Silva felt he’d been waiting too long, asked the umpire if he was going to call a time violation, and the ump immediately did so.  So that’s what the official was waiting for?

And of course, Cerretani had to argue about it, giving him another 30 seconds or more to rest before the next point.

I understand the arguments against a shot clock, especially if the clock were to be prominently displayed and generate excitement as it crept down to zero.  But the problem with the current system, regardless of the penalty for a first or second violation, is that it is so discretionary.  Sure, there are reasons that more time is required before some points, like moving the balls to the correct end of the court, or distractions in the audience.  So let the umpire (or some other official) reset the clock when those delays occur.

If tennis needs a time limit between points, that limit needs to be enforced fairly and consistently.  Until it is, no minor rule tweak is going to stop officials from selectively applying it–or ignoring it altogether.

Sao Paulo Challenger: Day One

Happy new year, fellow tennis geeks!

By chance, I found myself in Sao Paulo at the same time as the beginning of the first challenger of 2013.  Plenty of challengers these days are streamed online, so if you really want to see these guys play, you can swing it, but there’s still some magic to watching the action live.

Ok, well, “magic” might be a little strong for the first round of a South American challenger.  You know what I mean.

Before I dig into my notes on specific players, a couple of general issues:

Brazilian style. Brazil hasn’t had a major tennis star since the retirement of Gustavo Kuerten.  Many of the highest-ranked Brazilians are in Sao Paulo this week–on hard courts.  While Brazil, like the rest of South America, has traditionally been associated with clay courts, that is changing.  The 2016 Olympics event will be held on a hard surface, and Sao Paulo has hosted the challenger tour finals on indoor hard courts.

In time, I wouldn’t be surprised to see hard-court specialists emerge from this country and make an impact at the top range of the ATP rankings.  Many of the Brazilians kicking around the 100-200 range (Joao Souza, Rogerio Dutra Silva, Ricardo Hocevar) have an unworkable combination of hard-court games and clay-court tactics.  These aren’t Argentinian-style dirtballers–they back up their booming serves with aggressive groundstrokes and are rarely spotted more than a few feet behind the baseline.  But they still aren’t as aggressive as their games merit.  While Thomaz Bellucci has had the most success of his generation, his game has some of the same limitations.

As we’ll see in a moment, the next generation of Brazilians might have more pure hard-court success.  The additional hard-court exposure they are getting at home these days can’t hurt.

No-let serving. Finally, the ATP is following the lead of World Team Tennis and the NCAA … at least a little bit.  For the first quarter of this year, Challenger tournaments will abandon the “let” rule on serves.  If the ball lands in, it’s good, regardless of whether it made contact with the net.

In seven hours of tennis yesterday, I expected to see plenty of awkwardness around the no-let rule, since players haven’t had much time to adjust.  But that wasn’t the case.  Only once did a serve dribble over the net cord for an easy ace.  One or two other times the server had a late reaction, hitting a weak defensive return that he might improve on in another few weeks.  For the most part, the no-let rule didn’t raise an eyebrow.

The advantages are minor but very real.  I don’t think any fans like to see players argue pointlessly with chair umpires, and lets (real and imagined) have always been a source of friction.  No-let serving gives us smoother matches with fewer of those sorts of hiccups.

Now, on to the matches.

Guilherme Clezar (BRA) vs Thiago Monteiro (BRA)

The future of Brazilian tennis got off to an early start this morning.  Clezar, 20, was the top-ranked teenager in the world until his birthday yesterday.  Monteiro, 18, is the third-ranked 18-year-old in the world.

Both players have monster games, with big serves and crushing groundstrokes.  Monteiro, in particular, is capable of doing violence to the ball on his first offering.  And in fact, frequently Monteiro looked like the superior player, comfortably running around forehands to hit winners on tight angles.  But in this match, Clezar was the wily veteran, somehow breaking twice for the 6-4 6-4 win.

For all of Monteiro’s potential, he was erratic.  His low service toss led to a few patches of missed first serves. He lost his temper and earned a ball abuse violation when failing to run down a drop shot on an unimportant point early in the second set.

By comparison, Clezar played the part of the wily veteran.  The ball didn’t make quite as much noise off of his racquet, but he still hits awfully hard.  While Monteiro is a pure hard-courter, Clezar comes closer to the mold I mentioned above, using hard-court weapons in an occasionally clay-court manner.

Clezar’s groundstrokes were surprisingly varied, often dropping two or three forehands in a row within inches of the baseball, then hitting a heavier topspin shot that dropped short.  For all of his capabilities, though, he missed a lot of opportunities to follow up a strong serve with an equally aggressive second or third shot.  In this match, it didn’t stop him; against better players, it’s a major area for improvement.

Clezar’s impressive ranking (for a just-turned 20-year-old) is no mirage–he has the highest ceiling of any player I saw yesterday.  He has the raw tools for a Nicolas Almagro type of game; the next few years will show us whether he can be that good.

Diego Sebastian Schwartzman (ARG) vs Marcelo Demoliner (BRA)

The 20-year-old Schwartzman had an epic season at the futures level last year, and finally made any impact at higher levels in winning the Buenos Aires Challenger late last year.  Seeing him on a hard court, it’s tough to imagine him stringing those wins together.

The Argentine is short–5’6″ on the high side.  And while he does a lot with the limited tools he’s been given, he has a long way to go to get to the level of a once-in-a-generation talent like Olivier Rochus.  Schwartzman has the weakest serve I’ve ever seen in professional tennis, not putting much on first serves, but still frequently missing them.  He doesn’t even use a great deal of spin.

Demoliner, a big Brazilian who looks a bit like Juan Martin Del Potro, is hardly a top talent, but he didn’t have any trouble putting Schwartzman away.  To his credit, as the match progressed, he took a bit of gas off the serve and went for angles and spin, often leaving the Argentine to swing (and occasionally miss) at balls above his head.

The best comp for Schwartzman is probably Juan Ignacio Chela … with the caveat that Chela is tall.  Given the opportunity, I would imagine DSS sits back as far as he can go and outlasts his opponents.  It was clear yesterday that he’s very steady on the ground and is mentally strong for a 20-year-old, staying relatively focused under an attack he’s wasn’t going to overcome.  On slow clay, that’s a recipe for success, at least in challengers.  On any hard court, it’s barely worth showing up.  Indeed, it was only his fourth career pro match on hard, moving his record to 0-4.

Despite winning this match, Demoliner didn’t do much to impress.  As noted, he served intelligently, and often looked good coming forward, but he needed to be dragged to the net.  Again, we see a Brazilian with a big game who is reluctant to use it.

Martin Alund (ARG) vs Fabiano De Paula (BRA)

In pushing his ranking up to a career-high 119 last year, Alund played only two matches off of clay–first-round losses Wimbledon and US Open qualies.  For all that, he seemed surprisingly comfortable on hard courts.

That isn’t to say he was any more aggressive than the battalion of Brazilians I’ve commented on so far.  He has some of the tools for it, especially a big serve that he is able to effortlessly place in the wide corner.  His biggest advantage yesterday, though, was an opponent even less well-suited for the surface than he was.

De Paula occasionally looked great, stepping inside the baseline to hit one-handed backhand winners, and mixing in some impressive serving of his own.  More typically, you could see him four feet behind the baseline wondering what to do next.  Despite Alund’s passivity, De Paula proved he could play even more conservative tennis, squandering opportunities and trying to win 15-shot rallies that tended to end with an error on the 7th shot.

Alund, at 27, is unlikely to advance much further in the rankings, though he could easily hang around his current ranking by continuing his success in South American challengers.  De Paula has yet to break into the top 200, and he will need a new game plan if he’s going to help out his ranking with his hard-court performance.

Pedro Sousa (POR) vs Marco Trungelliti (ARG)

After watching so many players squander their firepower with poor tactics on Sao Paulo’s fast courts, it was refreshing to watch Trungelliti, a classic dirtballer who seemed happily unaware that he wasn’t playing on dirt.  Ultimately, he fell to Sousa in three sets, but by simply playing his game–unsuitable as it was–he looked more assured on the surface than the majority of others in the draw.

Sousa wasn’t comfortable at all.  He hit great shots, especially forehand winners from every position in every direction.  In trying, he sent balls sailing in every direction outside of the lines, as well.  He gave every evidence of mental instability as well, incessantly chattering at himself, and once standing at the net for 30 seconds trying to hit a ball to a ballboy with the grip of his racquet.

Both players, but especially Sousa, looked great when hitting groundstrokes in their strike zone; in less natural contact points, the results were less predictable.  Sousa’s forehand and Trungelliti’s two-hander could be particularly impressive.

Austin Krajicek (USA) vs Patricio Heras (ARG)

One final note, on a qualifying match that kicked off the day.  Three and a half years ago, I saw Krajicek in his first professional match, at US Open qualifying.  I left with a negative impression of an immature teenager with nothing like the game it would take to compete professionally, but then again, he was 18.

After a few years at Texas A&M, Krajicek is more mature, and has a few weapons that make him competitive at the challenger level.  But his game still seems awfully small for contemporary pro tennis.  Some first serves were strong, yet every second serve was weakly spun in.  He crushed some forehands, but almost every backhand was a defensive slice.  In a first-set tiebreak, he came to the net four times … only once behind a sufficiently good approach.

At 22, Krajicek has more time to develop, but for now, he’s far down the list of young Americans to watch.

The Structural Biases of Tiebreaks

There is more to tiebreaks than meets the eye. As we’ve learned recently, big servers don’t seem to have an advantage in tiebreaks over more balanced players, and very few professionals win more tiebreaks than we would expect them to.

In one of those discussions, commenter Håkon Mørk raised a related issue. Is the format of the tiebreak itself biased toward certain types of players? That is: Who benefits by playing tiebreak sets instead of “deuce” sets in which one player must win by a margin of two games?

When we put the question this way, it is straightforward. The primary beneficiaries of the tiebreak format are underdogs.

Think of it this way. The better player is likely to win, regardless of the format. The bigger the margin of victory required, the more likely the better player is to win. If Kenny De Schepper were to play a single tiebreak against Roger Federer, he’d have a decent chance of winning. But in a full-length set, that chance would be much lower. In a best of three match, lower still. Best of five: even lower. Best of five with no tiebreak in the final set: lowest of all.

Any change in the format of a tennis match that causes the match to hinge on fewer points gives the underdog a greater chance of lucking his way into victory.

On average, the underdog’s benefit from tiebreak sets isn’t much, compared to a hypothetical world in which the ATP played only deuce sets. For an individual set in the average tour-level 2012 match, the underdog’s chance of winning was 1.3% higher in a tiebreak set than they would have been in a deuce set.

But there’s more to the story. First of all, matches that are very close (in which both players win about 50% of points) drag down the average, since when the players are evenly matched, the format doesn’t matter — 50% is 50%. Second, matches that are very lopsided also drag down the average–if one player dominates, he has a very high percentage chance of winning a set regardless of the format.

Thus, in a somewhat closely (but not too closely) contested match, the underdog gains quite a bit more from the tiebreak format.

Structural biases

In some of these matches, the gain is much more than in others.

In fact, in six matches this year, the difference between the winner’s chance of winning a deuce set would have been more than ten percent greater than his chance of winning a tiebreak set.

(All of the chances I’m referring to are derived by calculating the winner’s winning percentages on serve and retun points, then running those through my set probability python code, which now provides an option for the probability of winning deuce sets.)

Two of the three most extreme such matches this year (and five of the top 14) were won by–could it be anyone else?–John Isner.

The most extreme case is Isner’s match against Janko Tipsarevic in the London Olympics. Isner won 84.7% of service points and 23.3% of return points, ultimately taking the match 7-5, 7-6(14). Those percentages translate to a 71.1% chance of winning a tiebreak set or an 84.1% chance of winning a deuce set.

If you were Isner, which would you prefer?

Compare that to a match between Jo Wilfried Tsonga and Xavier Malisse at the Miami Masters, which Jo won 7-5 7-5. This match went very differently than Isner-Janko. Tsonga won 68.1% of service points and 43.1% of return points. Those would give the Frenchman an 84.1% chance of winning a deuce set (sound familiar?) or an 82.7% of winning a tiebreak set.

This is just another illustration that fewer pivotal points gives the underdog a better chance. To win a tiebreak against Isner, you need to win one point against his serve (as long as you hold your own). To break an Isner service game, you need to win at least four.

Thus, an extreme big server like Isner appears to suffer from the tiebreak format. If the ATP went back to playing every set as a deuce set, he would have a much better chance of avoiding the lucky upset when he posts stats like those of the Janko match.

The big-serving underdog

There’s still more to this story. As we’ve seen, underdogs benefit from the tiebreak format: A structure with fewer points is more susceptible to luck. And big servers seem to be hurt by the tiebreak format.

What about when big servers are underdogs?

The tiebreak format isn’t biased against big servers, it’s biased against big servers who are better than their opponents. In matches already decided by a small number of points (like a couple of break points or minibreaks in an Isner-Federer match), the underdog benefits from playing tiebreaks.

And when one player has the big-serve/weak-return package, he effectively turns the other player into a bigger server and weaker retuner. We don’t usually think of Philipp Kohlschreiber as a big server, but when he played the serve-and-volleying Dustin Brown in Halle this year, he won 82.1% of service points and only 29.9% of return points. That type of match hinges on a very small number of points, and as such, gives the underdog a greater chance to pounce.

More mathematically speaking, the degree of the advantage given to the underdog by playing tiebreak sets is positively correlated with the overall percentage of service points won.

This presents something a conundrum for the big server. His style of play is beneficial in tiebreak sets while he is the underdog, but it becomes a hindrance once he is the favorite. When so many matches are decided by a single break or even a couple of minibreaks, a big-serving, weak-returning favorite will lose more than his share of matches he “should have” won, simply because of the way he plays.

One solution for such players is to win more tiebreaks than the numbers would suggest they should, as Isner does. Another tactic, of couse, is to hit better returns.

The Five-Set Advantage

Italian translation at settesei.it

Last night, the heavily-favored Janko Tipsarevic won his first round match against Guillaume Rufin despite dropping the first two sets.  Had Rufin taken the first two sets against Janko in Cincinnati, Monte Carlo, or just about anywhere else on the ATP tour, he would’ve scored his first top-ten scalp.

Other seeds have similar stories.  Milos Raonic, Marin Cilic, Gilles Simon, and Alexandr Dolgopolov all would be headed home had their matches been judged on the first three sets.  Only two seeds had the opposite experience: Juan Monaco and Tommy Haas were each up two sets to love before losing their next three.

Simply (if tongue-twistingly) put, the five-set format favors favorites.

In all grand slam first rounds since 1991, seeds have come back from 0-2 or 1-2 down against unseeded players 125 times, while seeds have squandered 2-0 or 2-1 advantages only 71 times.  Just looking at those 32 matches per slam, that’s almost one upset averted per tournament.  The US Open draw would look awfully different right now if Tipsarevic, Raonic, Cilic, Simon, and Dolgopolov were among the first-round losers, even if Haas and Monaco replaced them in the second round.

Set theory

These numbers shouldn’t surprise us, since longer formats should do a better job of revealing the better player.  There are reasons why the baseball World Series is best-of-7 instead of a single game and the final sets of singles matches aren’t super-tiebreaks.  The difference between best-of-3 and best-of-5 isn’t quite so simple–fitness and mental strength play a part–but from a purely mathematical perspective, there should be fewer upsets in best-of-5s than best-of-3s.

Take Raonic for example.  My numbers (which don’t differentiate between 3-set and 5-set matches–shame on me) gave him approximately a 70% chance of beating Santiago Giraldo.  If 70% is his probability of winning a three-set match and sets are independent (more on that in a minute), that number implies a 63.7% chance of winning any given set.  A 63.7% chance of winning a set translates into a 74.4% shot at winning a best-of-five.

A four- or five-point increase doesn’t radically change the complexion of the tournament, but it does make a different.  My original numbers suggested that we could expect 20 or 21 first-round upsets.  If we adjust my odds in the manner I described for Raonic, the likely number of upsets falls to 18.

The most important implication here is the effect it has on the chances that top players reach the final rounds.  Earlier this week a commenter took me to task for my unintuively low probabilities that Federer and Djokovic would reach the semifinals.  Obviously, if you give an overwhelming favorite a boost in every round, as the five-set format does, the cumulative effect is substantial.  For the top seeds, it can halve their probability of losing against a much lower-ranked opponent.

For Federer, adjusting the odds to reflect the theoretical advantage of the best-of-five format raises his chances of reaching the semis from 52.5% to over 65%.  Djokovic’s numbers are almost identical.

Dependent outcomes

Everything I’ve said so far seems intuitively sound, with one caveat.  Earlier I mentioned the assumptions that sets are independent.  That is, a player has the same chance of winning a particular set no matter what the outcome of the previous sets–there is no “hangover effect” based on what has come before.

Tennis players, even professionals, aren’t robots, so the assumption probably isn’t completely valid.  Sometimes frustration with one’s own performance, the environment, or line calls can carry over into the next set and give one’s opponent an advantage.  Perhaps more importantly, the result of one set sometimes reveal that pre-match expectations were wrong in the first place.  Had David Nalbandian played this week instead of withdrawn, no number of sets would reveal that he was a better player–his health would prevent him from playing at his usual level.

Another related caveat is that beyond a certain match length, the outcome is no longer dependent on the same skills.  When Michael Russell played Yuichi Sugita in the Wimbledon qualifying round, the two men looked equal for four sets.  In the fifth, Russell’s fitness gave him an advantage that didn’t exist in the first couple of hours.  In this case, an estimate of Russell’s probability of winning a set against Sugita may be independent of previous outcomes, but it is not the same for every set.

These allowances aside, there is little doubt that favorites are more likely to win best-of-five matches than best-of-threes.  Whether you want to watch the entire thing … that’s another story.

The Implications of the 10-Point Tiebreak

Italian translation at settesei.it

I’m not sure how we got here, but we now live in a world where a lot of people consider a 10-point tiebreak equivalent to a set.  Apparently it’s more fan-friendly and better for television.  And of course it’s faster.

Whatever its practical uses, it’s obvious that the first-to-10 breaker isn’t the same as a set.  I’ll leave the moral debate to others; let’s take a statistical approach.

In general, the more points (or games, or sets) required to win a match, the more likely it is that the better player wins.  Some commentators have taken to calling the 10-point breakers “shootouts,” and for good reason.  Reduce the number of points required to win, and you increase the role played by luck.

Of course, sometimes a shootout is the best idea.  You’ve got to end a match somehow, and when players end up equal after two sets, four sets, or four sets and twelve games, it’s all the more likely that luck will have to intervene.  But the structure of the match determines just how much luck is permitted to play a part.

To compare a 10-point tiebreak with the set it replaces, we need to know how much more luck it introduces into the game.  For that, we need an example to work with.

Take two players: Player A wins 70% of points on serve, and Player B wins 67% of points on serve.  Playing best of three tiebreak sets, Player A has a 63.9% chance of winning the match.

If A and B split sets, A’s probability of winning falls to 59.3%.  In other words, the shorter time frame makes it more likely that B gets lucky, or is able to put together an unusually good run of play long enough to win the match.

If the match is decided by a 10-point tiebreak, however, A’s probability of winning falls all the way to 56.0%, erasing more than one-third of the favorite’s edge in the third set.  In fact, the 10-point breaker is barely more favorable to A than a typical 7-pointer, in which A would have a 55.1% chance.

(If you like playing around with this stuff, see my python code to calculate tiebreak odds.)

Somehow I don’t think anyone would advocate replacing the deciding set with a 7-point tiebreak.  Yet a 10-point tiebreak is much closer to its 7-point cousin than it is to a full set.

Adding a few more points doesn’t resolve the discrepancy, either.  To maintain Player A’s 59.3% chance of winning, the third set would have to be replaced by a 26-point tiebreak.  But that, I’m sure, wouldn’t attract many new advertisers.