Defending champion Francesca Schiavone became the first woman to reach the fourth round at the French Open this year when Peng Shuai retired while trailing 6-3, 1-2 on Friday.
The fifth-seeded Schiavone has yet to lose a set at this year's French Open.
Peng broke in the third game then held for a 3-1 lead before Schiavone won five games in a row.
Peng called for a doctor after the first game of the second set and had her blood pressure checked. She looked exhausted sitting on her chair, even crying at one point, before breaking for a 2-0 lead.
Schiavone won the next game before her opponent retired.