Federer's Backhand.

The conventional wisdom is that Roger Federer's weakness, to the extent that he has one, is in his one-handed backhand. This is especially an issue against Rafael Nadal, who has traditionally, at least according to that same conventional wisdom, targeted attacks on Federer's backhand side with Nadal's high-bouncing lefty forehand. When Nadal gets that forehand kicking off the court, and makes Federer try to muscle an awkward one-handed backhand groundstroke from a hit point higher up towards his shoulder, it generally spells trouble for Federer.  

One of the key factors going into the 2017 Australian Open final would be whether Federer could handle the Nadal Forehand-to-Backhand Attack. 

As we know, Federer won. I certainly didn't expect it, but I had more hope that Federer could pull out the win this time for a few reasons. First, my belief that the courts were playing not only faster, but also with less bounce (thereby minimizing Nadal's crazy high bounce).  Second, this is the second major that Fed/Nadal have played since Federer went to the larger Wilson racquet head at the start of 2014.  While Nadal did win the 2014 AO semi-finals between them, Federer had just started playing with that larger racquet consistently at that tournament, so in my opinion it's tough to take much away that match.  To me, those two factors made what might otherwise be a 60/40 chance for Nadal and made it more of a toss-up.  

So I was very interested in seeing how Federer would be able to hit his backhand against Nadal, on that court, with that racquet - and to my eyes, he certainly succeeded on that front. Aside from the overall win, there are any number of points you could pick out from that final, and see how well Federer not only defended the backhand, but also used it offensively both cross-court and down-the-line.  Here's a video of all of his backhand winners from the match.

Unfortunately, we don't have publicly available data to see how the "bounce" might have affected Federer's backhand hit point. I believe that information is tracked - I think ESPN showed a graphic about the height of Federer's contact point at least once - but that data is publicly available, as far as I know.

However, we do have some other measures of the results of Federer's backhands - most notable coming from Jeff Sackman of the indispensable TennisAbstract.com.  Jeff found that, using a metric he calls Backhand Potency, Federer had the most success he's ever had in a Slam against Nadal, and by a huge margin. 

Jon Wertheim, who I generally like as a tennis writer and commentator, said something in his regular post-tournament "Mailbag", that got me thinking:

"...He played aggressive tennis -- note how few slices he hit...".  Jon doesn't specifically refer to the backhand slices here, but I think its safe to assume that's what he meant. I too watched the match and was taken aback by how often Federer seemed to hit "over" his backhand (meaning how often he hit top-spin or flat backhands, and conversely, how few slices he used).

But is this true? I'm a big believer that the "eye test" in sports is a terrible judge.  So did he actually use his backhand more aggressively (as shown by the ratio of how many slices he his as a percentage of total backhands)?  And does it even matter? Does being less aggressive - hitting a backhand slice instead of a top-spin/flat backhand - mean he's worse off against Nadal?  

Again, we can turn to TennisAbstract to try and find out. The Match Charting Project has documented every shot used in thousands of matches, and has charted 11 of the 12 Federer-Nadal majors matches (missing only the very first in 2005).

Here is a list of each match, with some key backhand groundstroke numbers.

The chart is self-explanatory, but since there are a lot of numbers here, let's look for some specific relationships in charts.

This shows the total number of Federer groundstrokes, and the number of backhand groundstrokes. The data points noted are solely to highlight the 3 wins Federer has in these matches.  This shows a relatively consistent, and intuitively obvious, pattern - as total groundstrokes go up, backhand groundstrokes go up as well.  When we look at it by percentage...

... we see no obvious connection to Federer's winning (the red bars) and the percentage of groundstrokes that are backhands.  His lowest percentage of backhands hit was actually the 2008 French Open...where Federer won a total of 4 games. Conversely, his 2017 Australian Open win was his 3rd lowest percentage. So no obvious pattern to me.

Now we look at how many backhand slices he's hit, as compared to overall backhand groundstrokes. All that jumps out from this view is that he's become more consistent in the aggregate number of slices hit as the years have gone on. While the total number of backhands rises and falls (related to the length of the matches, naturally), since 2012 or so, Federer seems to be making an effort to slice less, and hit over his backhand more. I wonder if we looked deeper into Federer matches if we've see that trend more generally (I assume we would) and if there would be an obvious "shift" point  (say, hiring Edberg as a coach).

Now does hitting less slices matter to winning against Nadal in majors?  Not obviously - again, look at his 2006 Wimbledon win - his 2nd highest number of slices, but one of his lowest total backhands hit. Looking at this as a percentage...

...we really see that 2006 Wimbledon win stands out here. Almost 40% of the backhands groundstrokes Federer hit in that win were slices. We see a similarly "high" percentage in his 2007 Wimbledon win. Fast forward 10 years, and Federer's "aggressive" backhand strategy - basically slice as little as possible - again stands out for the opposite reason.  

I think we can say that Wertheim's (and my) thought was probably true - Federer was aggressive with his backhands in the 2017 Australian Open, as shown by a reluctance to use slice backhands. Why a player chooses a particular shot obviously depends on many factors besides the player's overall game plan - not the least of which being how Nadal played (where he was hitting his balls, how deep and wide in the court, etc.).  But over the course of their long rivalry, Federer seems to be have become more committed to hitting through his backhands against Nadal.

Now whether Federer's tactic contributes to his winning - there's little evidence of that in their majors history so far. To be clear, it would be silly to try and point to one single thing as the "reason" for a tennis match result, and it would be even sillier to try and assign real value to these summary stats, when we're talking about a small sample of matches played over a decade.  But I enjoyed taking the look nonetheless.


... Again I'm right in my analysis!!