Djokovic v Federer by the numbers

Many of us were expecting an epic battle when No. 1 Novak Djokovic and No. 3 Roger Federer met in the semifinals of the Australian Open last night. But after the second set, Federer had just three games on the board and it looked like the end of the 45^th Djokovic-Federer confrontation was just around the corner.

Federer’s shot variety and aggressive approaches paid dividends in the third, eventually earning him the set. Yet, the Swiss couldn’t maintain the upper hand for long. In just nine more games, Djokovic would take the first 2016 win in their ongoing rivalry.

In the aftermath of the Djokovic-Federer semifinal, commentators will look at the match stats and break down the head-to-head. But something is lost when we focus only on how Djokovic and Federer have played against each other. Namely, we miss how the way they play against each other differs from how they play against all other opponents. To understand how Djokovic has gotten to be so effective against Federer, we have to consider how Federer’s typical game changes when he faces the No. 1.

To give more context to Djokovic’s semifinal win, the Australian Open data analytics team performed a Djokovic-Federer head-to-head analysis with a twist. In this head-to-head, we not only look at how Djokovic-Federer played in the semifinal and all of their 2015 meetings. We also considered how they each have performed against common opponents, who are the 24 players both Djokovic and Federer played in 2015.

How did they fare against common opponents?

Djokovic and Federer each dominated their common opponents in 2015. But did they both dominate to the same degree? Given that Djokovic called 2015 the best season of his career to date, we might assume that he won more convincingly than Federer. Yet, the differences in their dominance against common opponents was mixed.

Djokovic had the clear upper hand with respect to match wins in 2015, having a 43-3 win-loss record over Federer’s 37-4 record against the same opponents. Despite losing one more match than Djokovic, Federer actually won a higher percentage of sets, winning one more set than Djokovic for every 10 sets played. In terms of points, Djokovic won more return points, while Federer won more serve points against the same opponents in 2015.

The one area of the game where Federer consistently out-performed Djokovic against common opponents last season was on big points. Against the same opponents in 2015, Federer’s ratio of break-point opportunities earned against his opponents was almost double that of Djokovic. He was also more effective than Djokovic in converting break points than, winning five break points for every one of his opponent’s, while Djokovic won 2.5 break points for every break point won by the same opponents.

Djokovic’s effect on Federer’s game

Given Federer’s edge in clutch returning against common opponents in 2015, we would expect his record against Djokovic to be more in his favour. However, in his head-to-head record against Djokovic in 2015, Djokovic led their meetings in terms of matches, sets and games won.

These wins have come despite Federer creating many break point chances, though still fewer than Djokovic overall (53 versus 68). As we can see in the table below, Federer’s downfall, and where his performance has differed the most against Djokovic than any other opponent, is in break-point conversion. In their eight meetings in 2015, Djokovic won 22 breaks of serve, while Federer won only 13, close to half Djokovic’s conversion rate.

Djokovic has Federer’s number more than ever

The real story out of Rod Laver Arena last night wasn’t simply that Djokovic won but how he won. The ways that Djokovic affected Federer’s game in 2015 prepared us for a match in which Federer would have opportunities but might struggle to make the most of those chances. But in a display of near-perfect tennis, Djokovic took away all but four break point chances from Federer—all of which occurred in a single game in the third set. Federer wouldn’t see another chance to break for the rest of the match.

The way Djokovic was able to hold off any sustained threat from Federer makes the semifinal meeting at the AO a more definitive win than either of their two Grand Slam meetings last year. Djokovic’s semifinal win was a statement that he is going to be an even more serious threat to a Federer major in 2016 than we could have imagined.

Presented by the Australian Open analytics team in conjunction with Victoria University