Category Archives: Head-to-Heads

The Limited Value of Head-to-Head Records

Yesterday at the Australian Open, Ana Ivanovic defeated Serena Williams, despite having failed to take a set in four previous meetings. Later in the day, Tomas Berdych beat Kevin Anderson for the tenth straight time.

Commentators and bettors love head-to-head records. You’ll often hear people say, “tennis is a game of matchups,” which, I suppose, is hardly disprovable.

But how much do head-to-head records really mean?  If Player A has a better record than Player B but Player B has won the majority of their career meetings, who do you pick? To what extent does head-to-head record trump everything (or anything) else?

It’s important to remember that, most of the time, head-to-head records don’t clash with any other measurement of relative skill. On the ATP tour, head-to-head record agrees with relative ranking 69% of the time–that is, the player who is leading the H2H is also the one with the better record. When a pair of players have faced each other five or more times, H2H agrees with relative ranking 75% of the time.

Usually, then, the head-to-head record is right. It’s less clear whether it adds anything to our understanding. Sure, Rafael Nadal owns Stanislas Wawrinka, but would we expect anything much different from the matchup of a dominant number one and a steady-but-unspectacular number eight?

H2H against the rankings

If head-to-head records have much value, we’d expect them–at least for some subset of matches–to outperform the ATP rankings. That’s a pretty low bar–the official rankings are riddled with limitations that keep them from being very predictive.

To see if H2Hs met that standard, I looked at ATP tour-level matches since 1996. For each match, I recorded whether the winner was ranked higher than his opponent and what his head-to-head record was against that opponent. (I didn’t consider matches outside of the ATP tour in calculating head-to-heads.)

Thus, for each head-to-head record (for instance, five wins in eight career meetings), we can determine how many the H2H-favored player won, how many the higher-ranked player won, and so on.

For instance, I found 1,040 matches in which one of the players had beaten his opponent in exactly four of their previous five meetings.  65.0% of those matches went the way of the player favored by the head-to-head record, while 68.8% went to the higher-ranked player. (54.5% of the matches fell in both categories.)

Things get more interesting in the 258 matches in which the two metrics did not agree.  When the player with the 4-1 record was lower in the rankings, he won only 109 (42.2%) of those matchups. In other words, at least in this group of matches, you’d be better off going with ATP rankings than with head-to-head results.

Broader view, similar conclusions

For almost every head-to-head record, the findings are the same. There were 26 head-to-head records–everything from 1-0 to 7-3–for which we have at least 100 matches worth of results, and in 20 of them, the player with the higher ranking did better than the player with the better head-to-head.  In 19 of the 26 groups, when the ranking disagreed with the head-to-head, ranking was a more accurate predictor of the outcome.

If we tally the results for head-to-heads with at least five meetings, we get an overall picture of how these two approaches perform. 68.5% of the time, the player with the higher ranking wins, while 66.0% of the time, the match goes to the man who leads in the head-to-head. When the head-to-head and the relative ranking don’t match, ranking proves to be the better indicator 56.5% of the time.

The most extreme head-to-heads–that is, undefeated pairings such as 7-0, 8-0, and so on, are the only groups in which H2H consistently tells us more than ATP ranking does.  80% of the time, these matches go to the higher-ranked player, while 81.9% of the time, the undefeated man prevails. In the 78 matches for which H2H and ranking don’t agree, H2H is a better predictor exactly two-thirds of the time.

Explanations against intuition

When you weigh a head-to-head record more heavily than a pair of ATP rankings, you’re relying on a very small sample instead of a very big one. Yes, that small sample may be much better targeted, but it is also very small.

Not only is the sample small, often it is not as applicable as you might think. When Roger Federer defeated Lleyton Hewitt in the fourth round of the 2004 Australian Open, he had beaten the Aussie only twice in nine career meetings. Yet at that point in their careers, the 22-year-old, #2-ranked Fed was clearly in the ascendancy while Hewitt was having difficulty keeping up. Even though most of their prior meetings had been on the same surface and Hewitt had won the three most recent encounters, that small subset of Roger’s performances did not account for his steady improvement.

The most recent Fed-Hewitt meeting is another good illustration. Entering the Brisbane final, Roger had won 15 of their previous 16 matches, but while Hewitt has maintained a middle-of-the-pack level for the last several years, Federer has declined. Despite having played 26 times in their careers before the Brisbane final, none of those contests had come in the last two years.

Whether it’s surface, recency, injury, weather conditions, or any one of dozens of other factors, head-to-heads are riddled with external factors. That’s the problem with any small sample size–the noise is much more likely to overwhelm the signal. If noise can win out in the extensive Fed-Hewitt head-to-head, most one-on-one records don’t stand a chance.

Any set of rankings, whether the ATP’s points system or my somewhat more sophisticated (and more predictive) jrank algorithm, takes into account every match both players have been involved in for a fairly long stretch of time. In most cases, having all that perspective on both players’ current levels is much more valuable than a noise-ridden handful of matches. If head-to-heads can’t beat ATP rankings, they would look even worse against a better algorithm.

Some players surely do have an edge on particular opponents or types of opponents, whether it’s Andy Murray with lefties or David Ferrer with Nicolas Almagro. But most of the time, those edges are reflected in the rankings–even if the rankings don’t explicitly set out to incorporate such things.

Next time Kevin Anderson draws Berdych, he should take heart. His odds of beating the Czech next time aren’t that much different from any other man ranked around #20 against someone in the bottom half of the top ten. Even accounting for the slight effect I’ve observed in undefeated head-to-heads, a lopsided one-on-one record isn’t fate.


Filed under Forecasting, Head-to-Heads, Research

The 2014 Coach Smackdown

On the heels of the announcement that Boris Becker will coach Novak Djokovic, today we learned that Stefan Edberg will be part of Roger Federer‘s team for the first ten weeks of the season.  There will be more men’s Grand Slam champions in Australian Open coaching boxes than in the singles draw.

We’ve probably wrenched all possible commentary out of the head-to-head matchups of today’s slate of top players, so why not turn to their coaches instead?  Steve Tignor got us started:

I put together a list of 15 coaches and advisors, including Becker, Edberg, and Ivan Lendl, along with such names as Juan Carlos Ferrero, Goran Ivanisevic, and Michael Chang.  Many of them never played each other, since not all of their careers overlapped, but many of them did.

Becker, Edberg, and Lendl figure most prominently in these matchups, while Chang, Ivanisevic, and Sergi Bruguera also played plenty of matches against their fellow coaches.

Novak’s new coach barely edges out Andy Murray‘s coach as the king of his generation of advisors.  His 66-38 record against these 14 colleagues is slightly better than Lendl’s 47-28.  In eight of ten head-to-heads, Becker came out even or better. But one of those, as Tignor pointed out, is the matchup against Lendl, which the Czech leads 11-10.  If coaches can possibly accomplish such a thing, this pair might make Djokovic-Murray matches a little more interesting.

The other unfavorable head-to-head of Becker’s is my favorite quirky stat of the lot.  Twice in April 1993, when Becker was ranked fourth in the world, Franco Davin defeated him.  That’s a little better record for Davin than Juan Martin del Potro‘s 3-11 record against Djokovic.

Here’s the whole set of head-to-heads.  Don’t worry–in a few days the regular season will be back in full swing.

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Filed under Coaches, Head-to-Heads

Federer, Nadal, and Semifinal-or-Later Streaks

The Indian Wells men’s draw has been released, and a big question has been answered.  Rafael Nadal, about as dangerous a floater as can be imagined with a #5 seed, landed in Roger Federer‘s quarter.  (Sorry Roger, it had to happen to someone, and David Ferrer has suffered enough lately.)

If Fed and Rafa both win three matches, they’ll face each other in a quarterfinal match.  That’s something that’s never happened before.  The pair has met 28 times, 26 of them in a semifinal or final.  The only exceptions are their first match in 2004, when Nadal was seeded 32nd in Miami, and a round-robin pairing at the 2011 tour finals.  Ignoring the round-robin, that’s 26 matches in a row in one of the last two rounds of an event.

That’s a historically great streak, but it’s not the record.  In fact, one player is a part of two streaks–the only two streaks–that are better.

Jimmy Connors is 1st, with 28 consecutive semis or finals against Ivan Lendl, and 2nd, with 27 consecutive semis or finals against (who else?) John McEnroe.  He’s also eighth (21 straight against Bjorn Borg) and 12th (14 with Ilie Nastase).

Until the threat of this week’s draw, Federer and Nadal were right on Connors’s tail.  If Roger and Rafa meet in the quarters, the heir presumptive pair will have to include Novak Djokovic.

Here’s the all-time top ten:

Streak  Player1          Player2           
28      Jimmy Connors    Ivan Lendl        
27      Jimmy Connors    John McEnroe      
26      Rafael Nadal     Roger Federer     
23      Rafael Nadal     Novak Djokovic    
22      Stefan Edberg    Boris Becker      
22      Roger Federer    Novak Djokovic    
22      John McEnroe     Ivan Lendl        
21      Bjorn Borg       Jimmy Connors     
19      Stefan Edberg    Ivan Lendl        
17      Ivan Lendl       Boris Becker

If Nadal stays #5 for long (unlikely as that seems), both the all-time #3 and #4 streaks could be halted.  But as long as Federer stays within the top four, the current #6 streak will climb the rankings.

Of course, there are a couple of other combinations with the potential to crack this list, even reach the top:

Streak  Player1         Player2        
11      Andy Murray     Roger Federer  
10      Novak Djokovic  Andy Murray

But we shouldn’t get ahead of ourselves.  It took five years for Fed and Nadal to get from 11 up to 26.  As the top of the list shows, it takes two consistently great players to put together a streak like this.

All is not lost, though.  If they play in the quarters, they’ll just have to shift their focus to a new record: consecutive meetings in quarterfinals or later.  27 straight would put them behind Connors-McEnroe (32), Connors-Lendl (29), and one pair they’re unlikely to chase down: Nadal-Djokovic (29).

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Filed under Head-to-Heads, Jimmy Connors, Novak Djokovic, Rafael Nadal, Records, Roger Federer

The Most Familiar Faces

In last week’s Basel final, Roger Federer and Juan Martin Del Potro faced off for the seventh time this year, and the 16th time overall.  Seven times in one year is an awful lot, about 10% of Delpo’s matches.  It’s even more remarkable because only two of those contests have been finals — in order to meet so many times, the draws of several tournaments had to complement their consistently strong play.

Making matters even more extreme is that there is a better-than-50% chance that Federer and Del Potro will meet in London next week, bringing the total to 8.  And there’s a slim chance–if they are drawn in the same group, then play again in the final–that the sum will reach 9.

So, what’s the record?  Seven is already pretty good, right?

Single year head-to-heads

In fact, as with so many other records, Federer is #1 in the last 30 years.  He holds the record with Jo Wilfried Tsonga, against whom he played eight times last year.  (In the entire professional era, the mark belongs to Ilie Nastase and Tom Gorman, who played at least nine times in 1972.  I’ve excluded years before 1980 because a variety of factors caused the top players to meet much more frequently than they do these days.)

As long as Fed and Delpo are at seven, they will be tied with four other pairs: John McEnroe and Ivan Lendl in 1984, Jim Courier and Michael Chang in 1995, Novak Djokovic and Rafael Nadal in 2007, and Novak/Rafa again in 2009.  Another 11 pairs met six times in a single year, including Nadal and Djokovic in 2008 and 2011.  (Along with, weirdly, Rajeev Ram and Donald Young in 2007.  Must be the wild cards.)

All-time head-to-heads

Since Djokovic and Nadal show up at the top of the single-year list no more than four times, it stands to reason that they must be near the top of the all-time list, as well.  Indeed, they are.

In fact, assuming Nadal returns to health in anywhere near his historical form, this current pair of stars will almost undoubtedly take over the all-time lead next year.  They could hold it for a very long time.

Player 1       Player 2        H2Hs    W-L  
Ivan Lendl     John McEnroe      35  20-15  
Ivan Lendl     Jimmy Connors     34  22-12  
Pete Sampras   Andre Agassi      34  20-14  
John McEnroe   Jimmy Connors     34  20-14  
Rafael Nadal   Novak Djokovic    33  19-14  
Boris Becker   Stefan Edberg     32  22-10  
Roger Federer  Novak Djokovic    28  16-12  
Rafael Nadal   Roger Federer     28  18-10  
Stefan Edberg  Ivan Lendl        26  14-12  
Roger Federer  Lleyton Hewitt    26   18-8

This is one record that, for all of his dominance, Federer will probably never co-hold.  To find yourself on this list, you not only need to rank among the all-time greats, you need a very-near-contemporary who ranks just as high.

(If you’re interested in head-to-head records, I hope you’re already using the Head-to-Head Matrix on  It’s updated every week, and shows the career H2H records of every matchup within the current top 15.  Each H2H record is linked directly to a listing of the relevant matches.)


Filed under Head-to-Heads, Juan Martin Del Potro, Records, Roger Federer