Top-ranked Serena Williams lost in the second round of the Wuhan Open, retiring after 11 games on Tuesday and dropping a third match to Alize Cornet this year.
Williams, who won the U.S. Open just over two weeks ago, was leading 6-5 when she asked for treatment beside the court. The reason for the retirement was not immediately clear.
Cornet beat Williams at Dubai in February and had a third-round win at Wimbledon. The 24-year-old Frenchwoman hasn't lost to Williams this year and improved to 3-3 in career meetings.
The tournament's top two seeded players were eliminated within hours, with Williams exiting after Garbine Muguruza of Spain beat No. 2 Simona Halep of Romania 2-6, 6-2, 6-3.
Muguruza, who beat Williams in the second round at the last French Open, dropped the first set in 35 minutes but rallied to win the first four games of the second set and the last four games of the third to advance at the inaugural Wuhan Open.
It was a bad day for the seeded players on other courts, too. No. 10 Jelena Jankovic was trailing 4-1 when she retired against American player Coco Vandeweghe, Alison Riske of the United States recovered an early break to beat No. 11-seeded Sara Errani of Italy 6-4, 6-4, and Swiss qualifier Timea Bacsinszky defeated U.S. Open semifinalist Ekaterina Makarova, seeded 13th, 6-4, 6-1.
Eighth-seeded Caroline Wozniacki, however, held off Carla Suarez Navarro of Spain 6-1, 3-6, 7-6 (4).
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)