The Art of Defense: Who are the WTA Players with the Biggest Improvements in First Serve Return Skill?
After a week of competition under the Miami sun, it was Petra Kvitova and Elena Rybakina who faced off for the last women’s title of the Sunshine Double. Both competitors brought the full power of their serve to the match, each winning a staggering 79% of points on their first serve. Though serve advantage is more often recognized on the men’s tour, players like Rybakina and Kvitova show that the first serve can be as lethal on the women’s game and just as tricky an obstacle for WTA receivers to try to overcome.
When we look at skill on the first return, there are a handful of players who stand out as having most improved their defense against the most powerful stroke in the women’s game. Their first return skill trajectories since 2020 are shown in Figure 1, and one curve that immediately jumps out is that of Iga Swiatek. Swiatek is the player who gained the most skill in the shortest period of time, adding more than 400 rating points on first return over the 2021 season. Swiatek is also one of only several players charted who, for some period of time, consistently took the advantage away from the server on first serve points (Figure 2).
Defending at such a level that one expects to win close to 60% of first serve points when receiving are stratospheric levels of defense few players can maintain for long. We see that in Swiatek’s steady decline on first return since the end of 2021. Two other players have been on a similar downturn after reaching career highs on first return skill: Paula Badosa and Jelena Ostapenko. Badosa was in her best form on the first return at the start of 2022 after an especially strong show on defense at the Sydney Tennis Classic. Ostapenko was in high form at a similar time, some of her strongest attacks of the first return taking place at the 2022 Dubai Championships, which included a defense against Iga Swiatek that dropped the current World No. 1’s first serve win percentage down to 44%.
Figure 1. First serve return skill rating trends of WTA players with the largest gains in return skill since 2020.
Just as much as the sharp rise and falls of Swiatek, Badosa and Ostapenko stand out, the volatility in a few of the player trajectories is striking. The match-to-match ratings of Beatriz Haddad Maia looks more like a sine wave than a simple line, with two prominent peaks at the end of 2021 and the summer of 2022 that are both preceded by ratings declines approaching 1500. Sara Errani and Victoria Azarenka don’t show as systematic a pattern, instead there is a high variance in their first return skill, with ratings covering a several 100 points in any slice of the 2020 to 2023 seasons period. For these receivers, first return skill is defined more by it’s instability than anything else.
Figure 2. These plots show the implied first serve return win probability for the ratings in Figure 1 when facing the average first server skill these receivers have faced during the 2020 to 2023.
There are two players who are still riding an upward trend in first return gains. Ons Jabeur went from a mean first return rating of 1900 in the summer of 2021 to an average of 2200 the following year. In the last half of 2022, Jabeur’s return ability on first serve was at such a high that she was expected to win between 50 and 60% of first return points. Those odds no doubt contributed to Jabeur’s path to the finals of Wimbledon and the US Open last year. Some injury setbacks have seen a subsequent dip in Jabeur’s first return performance in 2023, but we will need more of the season to know if that will be a blip or a trend.
The first return trajectory that is most clearly on an upward trajectory into the current 2023 calendar is that of Amanda Anisimova. After an absence from competition at the start of 2021, Anisimova began to hit a stride on first return by the end of the 2021 season. Over the next year, Anisimova’s first return rating went from an average of 1900 to 2100, with her run at the 2022 Wimbledon’s being her strongest return performance of any one event that year.
Although Anisimova’s match results have been below expectation so far in 2023, this can’t be attributed to her first return skill, which has remained at a high level even through her recent losses. It may take the grass court swing, where Anisimova has been at her best in the past, to know whether Anisimova has simply had a streak of bad luck despite her defensive weapons or if the other skills in her arsenal have been letting her defensive game down.