Third-seeded Daniela Hantuchova of Slovakia and fourth-seeded Caroline Wozniacki of Denmark also advanced to the quarterfinals. Hantuchova beat Germany's Sabine Lisicki 6-0, 6-2 and will next face Sorana Cirstea of Romania, who beat Sara Errani of Italy 6-4, 6-2.
Wozniacki defeated Peng Shuai of China 6-4, 6-4.
Former top-ranked player Amelie Mauresmo needed three sets to beat Stephanie Gehrlein of Germany 6-2, 3-6, 6-0 and reach the second round. She will play Anna-Lena Groenefeld of Germany, who beat Yanina Wickmayer of Belgium 7-5, 6-4.