Weighing Options From the Backhand Corner

A few weeks ago, I offered a “first look” at the down-the-line backhand. I offered a stack of Match Charting Project-based stats showing how often players opted to play that shot, what happened when they did, how lefties differ from righties, and which players stood out thanks to the frequency or success of their down-the-line strikes.

Like Richard Gasquet returning a serve, we need to take a step back before we can move forward. Rather than continuing to focus solely on the down-the-line backhand, let’s expand our view to all shots played from the backhand corner. The DTL backhand is only one choice among many. A player in position to go down the line has the option of a cross-court shot or a more conservative reply up the middle. She also might run around the backhand entirely, taking aim with a forehand up the line (“inside-in”), down the middle, or cross-court (“inside-out”).

Every shot is a choice, and one of the roles of analytics is to analyze the pros and cons of decisions players make. Ideally, we would even be able to identify cases in which pros make poor choices and recommend better ones. We’re still many steps away from that, at least in any kind of systematic way. But thanks to the thousands of matches with shot-by-shot data logged by the Match Charting Project, we have plenty of raw material to help us get closer.

The first choice

In 2,700 charted men’s matches from the last decade (happy new year!), I isolated about 450,000 situations in which one player had a makeable ball in his backhand corner, excluding service returns. The definition of “makeable” is inherently a bit messy. For today’s purposes, a makeable ball is one that the player managed to return or one that turned into an unforced error. With ball-tracking data, we could be more precise, but for now we need to accept this level of imprecision.

Of the 450,000 makeable backhand-corner balls, players hit (non-slice) backhands 63.7% of the time and (non-slice) forehands 14.3% of the time. The remaining 22% were divvied up among slices, dropshots, and lobs, and we’ll set those aside for another day.

Here’s how 2010s men chose to aim their backhands from the backhand corner:

  • Down the line: 17.4%
  • Down the middle: 29.5%
  • Cross-court: 52.9%

And their forehands from the same position:

  • Down the line (inside-in): 35.1%
  • Down the middle: 12.8%
  • Cross-court (inside-out): 51.8%

The inside-in percentage is a bit surprising at first, though we need to keep in mind that it’s 35% of a relatively small number, accounting for only 5% of total shots from the backhand corner. Less surprising is the much higher frequency of shots going cross-court. Not only is that a safer, higher-percentage play, it directs the ball to the opponent’s backhand (unless he’s a lefty), which is typically his weaker side.

Point probability

Shot selection is only a means to an end. More important than deploying textbook-perfect strategy is winning the point, and that’s where we’ll turn next.

The average ATPer has a 47.7% chance of winning the point when faced with a makeable ball in his backhand corner. Of course, any particular opportunity could be much better or worse than that. But again, without camera-based ball-tracking data, we can’t make more accurate estimates for specific chances. We can get some clues as to the range of probabilities by looking at how they vary at different stages of the rally. When a player has an opportunity for a “serve-plus-one” shot in the backhand corner–the third shot of the rally–his chances of winning the point are higher, at 51.1%. On the fourth shot of the rally, when pros are often still recovering from the disadvantage of returning, the chances of winning the point from that position are 45.4%. Context matters, in large part because context offers hints as to whether certain shots are better or worse than average.

So far, we have an idea of the probability of winning the point before making a choice. There are two ways of looking at the probability after choosing and hitting a shot: the odds of winning the point after hitting the shot, and the odds of winning the point after making the shot. The second number is obviously going to be better, because we simply filter out the errors. By excluding what could go wrong, it doesn’t give us the whole picture, but it does provide some useful information, showing which shots have the capacity to put opponents in the worst positions.

Here are the point probabilities for each of the shots we’re considering. For each choice, I’ve shown the probability of winning the point after hitting the shot (“Post-Shot”) and after making the shot (“In-Play”).

Shot      Direction  Post-Shot  In-Play  
Backhand  (all)          48.2%    54.2%  
Backhand  DTL            51.4%    64.6%  
Backhand  Middle         44.2%    48.2%  
Backhand  XC             49.5%    54.6%  
                                         
Forehand  (all)          55.1%    63.0%  
Forehand  DTL (I-I)      58.5%    69.0%  
Forehand  Middle         47.3%    52.0%  
Forehand  XC (I-O)       54.9%    61.9% 

Forehands tend to do more to improve point-winning probability than backhands, though the down-the-middle forehand is less effective than a backhand to either corner. Again, this is context talking: A player who runs around a backhand just to hit a conservative forehand may have misjudged the angle or spin of the ball and felt forced to make a more defensive play. Still, it’s a relatively common tactic on slower clay courts (on clay, it is almost twice as common than tour average), and it may be used too often.

The most dramatic differences between the two probabilities are on the down-the-line shots. Both forehand and backhand are aggressive, high-risk shots, something reflected in the winner and unforced error rates for each. 9% of all shots from the backhand corner are winners, and another 11% are unforced errors. Of down-the-line shots, 23% are winners and 19% are unforced errors. While the choice to go down the line isn’t superior to other options, both the forehand and backhand are devastating shots when they work.

Player by player

Let’s tentatively measure “effectiveness” in terms of increasing point probability. Setting aside the complexity of context, which won’t be the same for every player, the most effective pro is the one who makes the most of a certain class of opportunities.

Here are the 10 best active players (of those with at least 20 charted matches) who do the most when faced with a makeable ball in their own backhand corner. Keep in mind that the average player has a 47.7% chance of winning the point from that position:

Player                Post-Shot  
Rafael Nadal              52.9%  
Diego Schwartzman         52.4%  
Novak Djokovic            52.3%  
Nikoloz Basilashvili      51.9%  
Andrey Rublev             51.8%  
Kei Nishikori             51.5%  
Gilles Simon              51.2%  
Pablo Cuevas              50.9%  
Alex De Minaur            50.0%  
Pablo Carreno Busta       49.6%

The Match Charting Project data might understate just how effective Rafael Nadal, Novak Djokovic, and Kei Nishikori are from their backhand corner, since a disproportionate number of their charted matches are against other top players. In any case, it is no surprise to see them here, along with such backhand warriors as Diego Schwartzman and Gilles Simon.

This list is limited to the tour regulars with at least 20 matches charted. One more name to watch out for is Thomas Fabbiano, with only 12 matches logged so far. In that limited sample, his point probability from the backhand corner is a whopping 59.2%. He isn’t quite that much of an outlier in reality, since his charted matches include contests against Ivo Karlovic, Reilly Opelka, and Sam Querrey, opponents whose ground games leave a bit to be desired. But his overall figure is so far off the charts that, even adjusting downward by a hefty margin, he appears to be one of the more dangerous players on tour from that position.

Forehands and backhands

Let’s wrap up by looking at something a bit more specific. For backhands and forehands (without separating by direction), which players are most effective after hitting that shot from the backhand corner? We’re continuing to define effectiveness as winning as many points as possible after hitting the shot. I’ll also show how often each of the players opts for their effective shot, giving us a glimpse at tactical decisions, not just tactical success.

Here are the best backhands from the backhand corner. It was supposed to be a top ten list, but I think you’ll understand why I struggled to cut it off before listing the top 16 players, roughly one-fifth of the 75 players with at least 20 charted matches:

Player                 Post-shot  BH Freq  
Diego Schwartzman          52.8%    74.0%  
Rafael Nadal               52.7%    64.7%  
Novak Djokovic             52.7%    76.1%  
Kei Nishikori              51.7%    74.0%  
Gilles Simon               51.4%    88.0%  
Andrey Rublev              51.1%    67.1%  
Pablo Carreno Busta        51.1%    75.3%  
Nikoloz Basilashvili       51.0%    75.0%  
Alexander Zverev           50.8%    75.1%  
Alex de Minaur             50.6%    74.8%  
Daniil Medvedev            50.6%    87.2%  
Juan Martin del Potro      50.3%    49.1%  
Pablo Cuevas               50.2%    60.6%  
Andy Murray                50.1%    65.0%  
Richard Gasquet            49.9%    75.8%  
Stan Wawrinka              49.8%    63.4%

The “BH Freq” column–for backhand frequency–really demonstrates the range of tactics used by different players. Gilles Simon and Daniil Medvedev opt for the topspin backhand almost every time, rarely slicing or running around the shot. At the opposite extreme, Juan Martin del Potro hits a topspin backhand less the half the time from that position. Perhaps because of his selectiveness–dealing with awkward positions by slicing–he is effective when he makes that choice.

Now the best forehands from the backhand corner:

Player                 Post-shot  FH Freq  
Gilles Simon               63.1%     6.7%  
Rafael Nadal               61.9%    16.6%  
Benoit Paire               61.9%     1.5%  
Kei Nishikori              61.2%    10.4%  
Andrey Rublev              61.0%    20.1%  
Casper Ruud                60.8%    27.1%  
Marton Fucsovics           60.5%    16.3%  
Novak Djokovic             60.0%     9.7%  
Daniil Medvedev            59.8%     3.3%  
Pablo Cuevas               58.9%    20.9%  
Sam Querrey                58.2%    15.6%  
Felix Auger Aliassime      57.7%    16.0%

This list is more of a mixed bag, in part because there are so many fewer forehands from the backhand corner. Benoit Paire’s numbers are based on a mere 21 shots. I wouldn’t take his effectiveness seriously at all, but it’s always entertaining to see evidence of his uniqueness. At the opposite end of the spectrum is Casper Ruud, who runs around his backhand more than anyone else in the charting dataset except for Jack Sock and Joao Sousa. (Neither one of which is particularly effective, though presumably they do better by avoiding their backhands than they would by hitting it.)

One name you might have expected to see on the last list is Roger Federer. He’s around the 80th percentile in the forehand category, winning 56.9% of points when hitting a forehand from the backhand corner. He’s good, but not off the charts in this category. Like Nadal and Djokovic, he might look better if these numbers were adjusted for opponent, because so many of his charted matches are against fellow elites.

Next

There’s clearly a lot more to do here, including looking at probabilities for direction-specific shots, isolating the effect of certain opponents, and trying to control for more of the factors that aren’t explicitly present in the data. Not to mention extending the same framework to other shots from other positions on court. Stay tuned.