Will a Back-To-Normal Federer Backhand Be Good Enough?

Italian translation at settesei.it

After Roger Federer’s 2017 triumph over Rafael Nadal at the Australian Open, I credited his narrow victory to his backhand. He came back from the injury that sidelined him for the second half of 2016 having strengthened that wing, ready with the tactics necessary to use it against his long-time rival. Since that time, he has beaten Nadal in five out of six meetings, suggesting that the new-and-improved weapon has remained a part of his game.

The Swiss is riding high after defeating Rafa once again in the Wimbledon semi-finals on Friday. But unlike in Melbourne two-and-a-half years ago, the backhand wasn’t responsible for the victory. In the Australian Open final, Federer’s stylish one-hander earned him 11 more points than in a typical contest, enough to flip the result in his favor. On Friday, Nadal had little reason to fear a Federer backhand that was only a single point better than average. The Swiss owes his semi-final result to some stellar play, but not from his backhand.

BHP redux

I’m deriving these numbers from a stat called Backhand Potency (BHP), which uses Match Charting Project shot-by-shot data to isolate the effect of each one of a player’s shots. The formula is straightforward:

[A]dd one point for a winner or an opponent’s forced error, subtract one for an unforced error, add a half-point for a backhand that set up a winner or opponent’s error on the following shot, and subtract a half-point for a backhand that set up a winning shot from the opponent. Divide by the total number of backhands, multiply by 100, and the result is net effect of each player’s backhand.

The average player hits about 100 backhands per match, so the final step of multiplying by 100 gives us an approximate per-match figure. BHP hands out up to 1.5 “points” per tennis point, since credit is given for both a winning shot and the shot that set it up. Thus, to translate BHP (or any other potency metric, like Forehand Potency, FHP) to points, multiply by two-thirds. In the 2017 Australian Open final, Federer’s backhand was worth +17 BHP, equal to about 11 points.

On Friday, Roger’s backhand was worth only +1 BHP. The best thing we can say about that is that it didn’t hold him back–the sort of comment we might have made as he racked up wins for the first 15 years of his career.

The semi-final performance wasn’t an outlier. In a year-to-year comparison based on the available (admittedly incomplete) MCP data, the 2019 backhand looks an awful lot like the pre-injury backhand:

Year(s)     BHP  
1998-2011  +0.1  
2012       +0.4  
2013       -1.8  
2014       -1.1  
2015       +1.3  
2016       -0.3  
2017       +3.5  
2018       +1.3  
2019       +0.8

There are still good days, like Fed’s whopping +16 BHP against Kei Nishikori in this week’s quarter-finals. But when we tally up all the noise of good and bad days, effective and ineffective opponents, and fast and slow conditions, the net result is that the backhand just doesn’t rack up points the way it did two years ago.

The backhand versus Novak

Federer’s opponent in today’s final, Novak Djokovic, is known for his own rock-solid groundstrokes. Like Nadal did for many years, Djokovic is able to expose the weaker side of Federer’s baseline game. The Serbian has won the last five head-to-head meetings, and nine of the last eleven. In most of those, he reduces Roger’s backhand to a net negative:

Year  Tournament        Result  BHP/100  
2018  Paris             L         -11.0  
2018  Cincinnati        L         -11.0  
2016  Australian Open   L         -12.6  
2015  Tour Finals (F)   L          -4.8  
2015  Tour Finals (RR)  W          +0.7  
2015  US Open           L          +0.8  
2015  Cincinnati        W          -2.2  
2015  Wimbledon         L         -13.4  
2015  Rome              L         -12.2  
2015  Indian Wells      L          -5.0  
2015  Dubai             W          -5.9  
…                                        
2014  Wimbledon         L          -3.1  
2012  Wimbledon         W          +9.6

Out of 438 charted matches, Federer’s BHP was below -10 only 27 times. On nine of those occasions–and two of the five since Fed’s 2017 comeback–the opponent was Djokovic. Incidentally, Novak would do well to study how Borna Coric dismantles the Federer backhand, as Fed suffered his two worst post-injury performances (-20 at 2018 Shanghai, and -19 at 2019 Rome) against the young Croatian.

It is probably too much to ask for Federer to figure out how to beat Djokovic at his own game. The best he can do is minimize the damages by serving big and executing on the forehand. The Swiss has a career average +9 Forehand Potency (FHP), but falls to only +4 FHP against Novak. In last year’s Cincinnati final, Djokovic reduced his opponent to an embarrassing -13 FHP, the worst of his career. It wasn’t a fluke: four of Fed’s five worst single-match FHP numbers have come against the Serb.

If Federer is to win a ninth Wimbledon title, he’ll need to rack up points on at least one wing–either his typical forehand, or the backhand in the way he did against Djokovic in the 2012 semi-final. Whichever one does the damage, he’ll also need the other one to remain steady. His forehand was plenty effective in the semi-final against Nadal, worth +12 FHP in that match. Against a player like Novak who defends even better on a fast surface, Federer will need to somehow tally similar results. It’s a lot to ask, and one thing is certain: No one would be able to complain that his 21st major title came cheaply.