Playing with Fire: Stories of Recent Second Serve Progress on the WTA
The second serve is often considered the Achilles’ heel of many tennis players, and for good reason. With nearly 40% of service points on the WTA starting with a second serve, a weak or inconsistent shot choice can spell disaster for even the most talented players. But while the second serve may be a source of anxiety for some, it is also an area where players can make significant strides in their game. In this blog post, we will look at gains in second serve skill ratings to highlight some of the recent stories of second serve progress on the women’s tour.
In the last three years, there have been twelve active WTA players who have added 180 points or more to their second serve skill rating (Figure 1). Iga Swiatek is the most highly rated player of the three who gained between 180 and 190 rating points, the other two being Elise Mertens and Raluca Serban. Each of these players is continuing on an improving trend for their second serve, with both Mertens and Serban getting there after a period of decline. Serban’s turnaround has helped her to advance to more consistent play at the WTA level. For Mertens, the gains in second serve skill coincided with a title win in Monastir.
Swiatek second serve skill improvement has followed a more linear trend over the past three seasons, but with a large amount of variance in any one period. At her current level, Swiatek is expected win 62% of points on her second serve on average (Figure 2) but with a variance of 60 to 72%.
The next three among the most improved are Magdalena Frech, Dalila Jakupovic and Shuai Zhang. Each of these players had gains between 230 and 250 points in second serve skill, Shuai Zhang being the most improved of the group. Zhang was at her highest level on second serve in the summer of 2022 when she had several good results on grass, including reaching the finals at Birmingham.
Figure 1. Second serve skill rating trends of sample of WTA players with large changes in skill on the second serve.
Elena Rybakina is the most highly rated in the next group of most improved, with a current second serve skill rating of 2230. Along side Alison Riske and Tatjana Maria, Rybakina are among players who have had added 260 to 300 points on second serve skill. Tatjana Maria has seen the steepest rise of the three, with the majority of her gains happening within the past 12 months. Rybakina’s rise has been more steady but, with two premier finals and one Grand Slam final in 2023, it has been achieved against the strongest opposition. At her current level, Rybakina is expected to win 66% of points on second serve even against top WTA receivers.
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.
Only three players among the most improved have gained 330 points or more in second serve skill: Jil Teichmann, Anna-Lena Friedsam and Veronika Kudermetova. Kudermetova has attained the highest skill rating of the three and she currently stands at 2135 rating points on second serve. Kudermetova’s pattern of improvement is one of the strangest of the group. Kudermetova seemed to be on a path of improvement going into the summer of the 2021 season but she then had a precipitous drop off in form over the next 6 months. Kudermetova went on a tear in the first months of the 2022 season and reached a career-high second serve rating of 2300 by the summer.
Despite her recent success, Kudermetova has already shown some signs of faltering on her second serve this year, after multiple first round exits since Dubai. With the clay season in full swing, the question remains whether she will be able to maintain her newfound second serve prowess on the slower, more demanding surface. Kudermetova is off to an impressive start in Madrid and only time will tell if that can continue.