Hsieh, Errani, and a Match That Broke Everybody

In their third round match today at the Australian Open, Sara Errani and Su Wei Hsieh played 232 points. The fastest serve either one hit registered at 93 mph (149 kmh), Hsieh’s first serves averaged 85 mph, and Errani’s mean first serve speed was 75 mph. I use the word “mean” here as more than just a way to avoid saying “average” so many times.

The two veterans are crafty–dare I say tricky–players with an arsenal of weapons once the ball is in play. But the serve is mostly just a stumbling block to make the best of. Hsieh won 62 of her 115 return points, good for 54% of Errani’s serves. This is more impressive than it sounds–the Italian double faulted only four times today. It’s fairly common for a winner on the women’s tour to win more than half of her return points, but what makes this match so weird is that Errani did the same. She won 63 of her 117 return points, also a 54% clip.

About half of WTA losers fail to convert better than 50% of their service points. But only 2.4% of winners miss the mark. And there’s a huge gap between 50%–mediocre and survivable–and Hsieh’s 46%. A 46% rate of service points won translates to a 40% likelihood of holding. Coincidentally, that’s exactly what both players did, each hanging on to their service games in 6 of 15 tries.

I have the relevant stats for just under 25,000 tour-level, main draw women’s matches since 2010, and only about 80 winners–0.3%, or less than once per 300 contests–won service points at a lower clip than Hsieh did today.

** I say “about” because the stats I have from the early 2010s aren’t perfect. A match with 60% of return points won is a prime candidate to be a mistake. I checked these 80 for obvious errors, like matches with a small number of service breaks, but those numbers aren’t perfect either.

There’s no grand analytical insight to be gleaned from a match like this. It’s just a glorious oddity that reminds us how many different ways there are to win matches. (And to be honest, you only need to watch Hsieh for about 90 seconds to recognize that.) In that spirit, here’s some more trivia:

  • Since 2010, this is only the 12th Australian Open main draw match in which neither player won half of her service points.
  • The only AO match in which neither player won 46% of their service points was the 2018 third-rounder between Anett Kontaveit and Jelena Ostapenko. They both held about 45.5% of their points, and 68% of total games (17 of 25) were breaks.
  • There have been about 400 tour-level matches since 2010 in which neither player wins half of their service points. Before today, 21 of those involved Errani, and she won 17 of them.
  • The other players who have been involved in at least 12 such matches are Monica Niculescu (16), Alize Cornet (14), and Carla Suarez Navarro (13). Today was only Hsieh’s 5th appearance on the list.

Perhaps oddest of all, this the first time in four tries that Hsieh avoiding getting bageled by Errani. Last time they played, in Istanbul in 2017, the Italian won, 6-0 6-1, needing only 55 minutes and a total of 87 points. Errani was so on-form that day that she won a whopping 66% of her service points. Hsieh finally turned the tables, even if she still hasn’t figured out how to stop this dogged opponent from breaking her serve.

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