AO Leaderboard - Rally Lengths

December 03, 2016

Rally lengths are a useful measure for differentiating styles of play. Players who tend to keep points to a few shots would be expected to be dominant on serve and more willing to go to net. Players who tend to grind out extended rallies would tend to be the baseliners whose best weapons are their groundstrokes and endurance.

Some analysts have characterised the professional game as first strike tennis, because the majority of points are 4 shots or fewer (counting the serve). Although it is the typical pattern for players to end points on or before the returner has made their second shot, we know that there is a lot of player-to-player variation in this pattern.

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Continuing the AO Leaderboard series, this post digs into that question of player differences in rally lengths. The specific questions we look at are who are the fastest and longest ralliers in the game? And which servers get into the longest rallies on their second serve? The first question tells us about a player’s overall rally tendencies and, hence, their playing style. The second question tells us more about the vulnerability of the second serve. If a player is much more likely to get into an extended rally on their second serve, it would be an indication of a weak second serve.

All of the summaries that follow were produced by the Game Insight Group of Tennis Australia and are based on matches from the 2014 to 2016 Australian Open. The definition of rally shown here counts all shots starting with the serve.

Using the first strike threshold to differentiate short from long rallies, we see that 90% of top players have a frequency of getting into a rally length of more than four shots that is somewhere between 20 and 36% (Figure 1). The player who has done the best job of keep rallies short at past AOs is American Jack Sock, who had only 18% of points over 4 shots in length (No wonder he’s won of the best doubles players in the sport). Clustered around Sock are other strong servers who aim for short points, including Sam Groth, John Isner and Vasek Pospisil.

Although Rafael Nadal is regarded as playing unusually long rallies, we find that, at least on hard court, he is fairly typical. In fact, Nadal’s frequency of 28% of rally lengths over 4 shots puts him behind Andy Murray and Novak Djokovic, who each get into long rallies 34% of the time on hard court, making them two of the longest ralliers in the game.

When we look at how the typical rally lengths change on a player’s second serve, we see that most players are much more likely to get into long rallies on these points than other points. Take Nicolas Almagro, for example. Almagro tends to keep rallies very short on most points (whether serving or returning), as he gets into long rallies only 20% of the time. Yet on his second serve, that percentage shoots up to 38%.

There are some interesting exceptions to this pattern. Big server John Isner is a really interesting one. He actually has even shorter rallies on second serve, which could be a small sample size effect owing to the small number of second serve Isner plays or be an indication that all of his serves are very effective.

A less obvious exception is Fernando Verdasco, who maintains an equal frequency of rallies on all points and second serves, suggesting that his strategies on second serve would be worth a closer look.

Longer rallies on the WTA are more common, with 90% of top women players having frequencies of long rallies between 23 and 44% (Figure 2). As with the men, we see some of the most effective servers and attacking players among the short ralliers. Karolina Pliskova, Serena Williams, and Petra Kvitova are all included in this group and have long rallies only 23 to 24% of the time.

On the other end of the spectrum, we find Angelique Kerber, Simona Halep, and Victoria Azarenka among the longest ralliers in the women’s game. Each of these players have gotten into rallies of more than 4 shots more than 40% of the time at past AOs.

In contrast with the men’s game, we find much more variation in differences between average rally lengths and rally lengths on second serves among female players. We see, in particular, a larger subset of players who have shorter rallies on second serve than their average rally lengths, including Camila Giorgi and Flavia Pennetta. It seems from this that, while the serve might be less dominate on the women’s game, it could make for a more interesting variety of playing styles.