Nikola Bartunkova vs Aryna Sabalenka — R32 — China Open

Nikola Bartunkova beat second seed Aryna Sabalenka in straight sets in the China Open round of 32, holding serve throughout. Sabalenka had been an 83 percent favorite in the betting market. She came in 34-4 on hard courts this season, including a run to the US Open final last month. Bartunkova, a 20-year-old Czech seeded 26th, began the season ranked 126th and is now WTA No. 34. She won the opening set of their only previous meeting on record, a grass-court quarterfinal at the Berlin Tennis Open in June, before Sabalenka took the next two sets. In Beijing, all five of Sabalenka's break points came in the first set, and she converted none. She did not earn another in the second, while Bartunkova broke once in each set. Bartunkova landed only 51 percent of her first serves but won 26 of the 32 points when she did. Sabalenka won 27 of her 50 first-serve points, well short of the 72 percent she has won on hard courts this season. The result sends Bartunkova into the round of 16 with her highest-ranked win on record. Her previous best was a January victory over then-WTA No. 10 Belinda Bencic at the Australian Open.