Third-seeded Samantha Stosur extended her perfect record against Hsieh Su-Wei of Taiwan to reach the quarterfinals of the Strasbourg International on Tuesday.
The 2011 U.S. Open champion, who never dropped a set in her three previous matches against 83rd-ranked Hsieh, secured a 6-3, 7-6 (3) win and will be up against Caroline Garcia of France next.
"It was another good match against a tricky opponent. It was closer than the score looked," Stosur said.
Alla Kudryavtseva of Russia also advanced after rallying past Zarina Diyas of Kazakhstan 4-6, 6-4, 7-6 (4).
The outdoor clay-court event is a warmup for the French Open, which starts on Sunday.