Top seed Marion Bartoli was forced to retire during the opening set of her first-round match at the Guangzhou International Women's Open.
Bartoli, currently ranked 10th in the world, was trailing 4-3 to qualifier Kai-Chen Chang before a gastrointestinal illness led to her withdrawal from the match.
Home hope Jie Zheng, the tournament's second seed, also benefited from a retirement in her opening-round match when opponent Yung-Jan Chan pulled out while trailing 5-3 in the first set. Dizziness was citing as the reason for her pull-out.
Zheng will meet Britain's Laura Robson in the second round after her victory over Maria-Teresa Torro-Flor on Monday.
The third and fourth seeds also eased into the second round as Sorana Cirstea and Urszula Radwanska beat Yue-Yue Hu and Melinda Czink, respectively.
However, there was an upset elsewhere with Mathilde Johansson of France beating sixth seed Monica Niculescu in straight sets.
Thai qualifier Nudnida Luangnam progressed with a 6-7 (5/7) 6-4 6-2 victory over Jarmila Gajdosova.
There were also wins for Su-Wei Hsieh, Alize Cornet, Olga Govortsova and the Chinese trio of Shuai Peng, Ying-Ying Duan and Saisai Zheng.