Who Can Stop John Isner?

Last week, John Isner beat world number one Novak Djokovic.  Earlier this year, the victim was Roger Federer.  At least year’s French Open, Rafael Nadal had to go to five sets to eliminate the big man.  Between Isner’s massive serve and the general improvement in his game, it seems that he can beat anybody.

To beat big John, you need either a strong return game or solid tiebreaker skills.  Ideally, you’d have both.  (The only alternatives are to catch him on an off-day or to play him on a slow clay court.)  Let’s take a look at how opponents have fared against the Isner serve over the course of his career.

One surprising indicator of return prowess is ace-rate-against.  We tend to think of ace rate as a function only of the server’s ability, perhaps coupled with surface speed.   But returner’s have plenty to say about it, too.  Simply looking at Isner’s 17 tour-level matches this year, we see a remarkable range of ace rates, from 36.6% of points against Gilles Muller in Memphis down to 5.6% against Federer in Indian Wells.  Surface plays a role, as do a variety of other factors (maybe Isner was tired after beating Djokovic in the semifinal last week), but some players are considerably better than others at getting the ball back in play.

A thorough look at that phenomenon is a subject for another day.  There’s plenty to do simply comparing performances against Isner.  As I’ve noted before, a big serve doesn’t necessarily make a player more unpredictable, though of course such a weapon might make him a better player.

63 players have faced Isner at least twice in tour-level events.  Of those, the most effective has been Lleyton Hewitt, holding Isner’s ace rate under 10% and winning almost half of Isner’s serve points.  However, the most recent of those two matches was almost two years ago.  Still, it’s not surprising to see a world-class counterpuncher atop this list–Hewitt limits aces and service holds against just about everybody.

We find more of the same near the top of the list, with Juan Ignacio Chela, Gilles Simon, and Nikolay Davydenko all in the top 10, ranked by the rate of return points won.  Height might also help in handling the physics-defying bounces of the Isner serve: both Tomas Berdych and Juan Martin Del Potro are among the top 15, though some other tall guys (Kevin Anderson and Ivo Karlovic are shown below) have generally weak return games, so the argument doesn’t seem to apply to them.

The unexpected contrast on this list is to find Nadal several spots below Djokovic, Federer, and Andy Murray.  Nadal allows about the same ace rate as Djokovic and Murray, but he doesn’t perform as well on the balls he gets back in play.  One popular theory is that because of his height, Isner is able to neutralize some of Rafa’s spin.  Regardless of the reason why, it’s even more unexpected to see Rafa so far down the list, since two of the three Nadal-Isner matches have taken place on clay.

Here are some of the raw results for players who have faced Isner two or more times.  I’ve shown the 20 opponents who have won the most return points, along with ten other notable players, whose ranks (out of 63) are shown in parenthesis.

Opponent                 SvPts  Matches   Ace%  SvPtsWon  
Lleyton Hewitt             124        2   8.9%     53.2%  
Tomas Berdych              300        3  11.7%     57.7%  
Thiemo De Bakker*          165        2   9.1%     60.0%  
Mikhail Youzhny            258        2  16.3%     61.6%  
Juan Ignacio Chela         269        3   6.7%     62.1%  
Novak Djokovic             191        2  14.1%     62.3%  
Andy Murray                224        2  13.8%     62.5%  
Roger Federer              243        3  11.5%     63.0%  
Gilles Simon               244        2  15.2%     63.9%  
Nikolay Davydenko          248        3  18.5%     64.1%  

David Ferrer               326        4  14.7%     64.4%  
Viktor Troicki             234        3   9.0%     64.5%  
Juan Martin Del Potro      201        3  16.4%     64.7%  
Robin Haase                233        2  15.0%     64.8%  
Rafael Nadal               336        3  13.7%     64.9%  
Richard Gasquet            221        2  19.0%     65.2%  
Marat Safin                115        2  13.9%     65.2%  
Mardy Fish                 424        4  13.4%     65.6%  
David Nalbandian           259        2  19.7%     65.6%  
Feliciano Lopez            207        2  19.3%     66.2%  

(22) Jurgen Melzer         177        2  16.4%     66.7%  
(25) Fernando Gonzalez     185        2  16.8%     68.6%  
(27) Gael Monfils          651        6  15.4%     69.1%  
(29) Andy Roddick          466        5  20.0%     69.5%  
(32) Jo Wilfried Tsonga    227        2  13.2%     70.5%  
(40) Kevin Anderson        443        6  16.9%     71.6%  
(41) Ivo Karlovic          289        3  15.9%     71.6%  
(46) Lukasz Kubot          167        2  21.0%     73.1%  
(57) Alex Bogomolov Jr     221        3  23.1%     77.4%  
(63) Andrey Golubev        127        2   9.4%     84.3%

(De Bakker gets an asterisk because one of his two matches immediately followed Isner-Mahut, and John was playing injured.)

An interesting avenue for further research is whether return quality against Isner differs much from return quality against players in general.  Sure, Isner wins more points on serve and hits more aces, but looking at the list above, it doesn’t seem to differ much from a ranking of the game’s best returners.  For all of his uniqueness, he’s simply one very big server in a game full of big servers.  As he goes deeper in more tournaments, perhaps we’ll gain a better grasp of what players need to do to stop him.