Mastering the Tightrope: Stories of Recent Second Serve Progress on the ATP
In tennis, the second serve is often described as the most vulnerable shot in the game. The pressure not to double fault while still putting your opponent at a disadvantage is immense, and one misstep can mean the difference between winning and losing a crucial point. But when we look at recent trajectories of second serve skill, it is possible to find ATP players who – for at least some time – have raised their second serve performance to career-high heights. With the second serve making up 37% of total service points on average for top ATP players, significant gains in second serve can be truly game-changing.
When we look at progress in second serve skill, players who achieved the largest gains over the past two seasons added 100 points or more to their skill rating (Figure 1). Five of these players haven’t been able to consistently maintain their peak performance on second serve. Alex De Minaur’s second serve skill rating peaked above 1900 after a string of strong performances in the first months of the 2022 season but has been steadily dropping and is now at 1750. We see a similar pattern for Arthur Rinderknech and Steve Johnson. The drop in performance was especially stark for Johnson after setting the tour ablaze on second serve in the end-of-year hard court swing in 2021. Johnson was close to achieving a second serve skill rating of 2100 with that run but quickly dropped 100s of points from that high.
Stefanos Tsitsipas and Taylor Fritz are the only two other players who have gained and lost a similarly high level of second serve performance. Each were in top form at the end of the 2021 season at which time they were serving in a range that was expected to earn them 60-65% of points on second serve over the average receiver they faced (Figure 2). Their declines have been more gradual than for De Minaur, Rinderknech, and Johnson, but the losses are still notable. At their current levels, Tsitsipas and Fritz are expected to win closer to 55% of points on their second serve.
Figure 1. Second serve skill rating trends of sample of ATP players with large changes in skill on the second serve.
For David Goffin and Borna Coric, their second skill trajectory is a story of recovery. We can see each with a period of absence from competition – an especially long period for Coric – followed by an upward trend in second serve ability. The gains have been particularly steep for Coric who is now regularly winning more than 60% of points on second serve.
Casper Ruud has one of the more irregular patterns of the group. He too has seen an improvement in second serve performance over the last 6 months. However, his results are some of the noisiest of his competitors. For the last half of the 2022 season, for example, Ruud’s second serve rating ranged between 1700 and 2000. This could reflect true inconsistency or some situation-specific edge, like a new-found serve advantage on clay.
Figure 2. These plots show the implied first serve win probability for the ratings in Figure 1 when facing the average receiver skill among the receivers faced by this group of servers.
For the remaining players, the pattern of improvement is the most promising because their skill is continuing to trend in a positive direction. The stand outs among this type of most improved are without question Nicolas Jarry and Jannik Sinner. Both Jarry and Sinner have risen in the second serve ratings in tandem since the summer of 2022. And for both the rise came after a period when their second serve appeared to be falling off. That kind of struggle followed by a sudden and sharp rise could be a sign of a phase or re-working on serve where they were both worse off before achieving a sudden turnaround.
Sinner is the most improved on second serve of all ATP players in recent years, having jumped close to 300 points in his second serve skill rating in just the past year. At this time, Sinner is also one of the highest rated players on second serve overall. During the clay court season this year, we can expect Sinner to win 65% of points on his second serve on average. With the kind of momentum we can see in Sinner’s second serve ability, where the steep gains aren’t yet showing a sign of tapering off, it is no coincidence that Sinner has reached four event finals so far this year. A big question for Sinner for the rest of this year is how much longer he can sustain these formidable trends.