WUHAN, China — Top-seeded Aryna Sabalenka saved nine match points before eventually losing in three sets to Ann Li at the Wuhan Open in a dramatic last-32 match that saw the four-time major winner requiring treatment on her taped-up right knee.

Li came from 4-2 down in the second set to beat Sabalenka, a three-time champion, 3-6, 6-4, 7-6 (5), with the American clinching victory off her 10th match point — but the first on her own serve.

It is now two straight losses for Sabalenka, who was beaten by Nikola Bartunkova in the Round of 32 at the China Open. Her previous event had been the U.S. Open, where she lost in the final to Elena Rybakina.

Sabalenka was trailing 4-1 in the deciding set when she had treatment on her right knee that already was taped, and was then 5-2 down before recovering for 5-5 and took it to a tiebreaker. Li delivered a big forehand winner on her last match point for one of the biggest wins of her career.

Earlier, the second-seeded Jessica Pegula squandered three match points and lost to Jelena Ostapenko in three sets in the American’s first match in more than a month.

Ostapenko won 2-6, 7-6 (7), 6-3 in an unlikely last-32 comeback that included saving match points on three occasions in the second set against Pegula, who hadn’t played since losing to Sabalenka in the U.S. Open semifinals.

Pegula, a finalist in Wuhan last year, took an extended break — missing events in Singapore and Beijing — because of the physical toll of her busy schedule over the summer.

Iga Swiatek had a much easier time of it, advancing to the round of 16 with a 6-2, 6-1 win over Magdalena Frech.

The six-time major winner started slowly against her Polish compatriot, dropping an early service game and falling behind 2-0 before winning six straight games to take the first set. She continued momentum by winning four straight games to start the second set.

Swiatek is seeded No. 7 in the WTA’s 1,000-level event. She reached the quarterfinals of the recent China Open in Beijing.

In other second-round matches, No. 5 Elina Svitolina had a 6-2, 5-7, 6-2 win over Liudmila Samsonova and No. 170-ranked Sonay Kartal upset No. 9-seed Belinda Bencic 6-0, 7-5. Sixth-seeded Karolina Muchova beat Caty McNally 3-6, 7-6 (1), 7-6 (4) and next faces Diana Shnaider.