The ninth-seeded American was comprehensively outplayed in the opening set of their third-round tie on Thursday, but hit back to wrap up a 1-6 6-3 6-2 victory in one hour and 42 minutes. Williams was broken three times in the first set by her Danish opponent, seeded sixth, but turned the tables on Wozniacki with four breaks of her own over the next two sets. “I had a slow start today, I don’t know why,” said the 30-year-old. “I was sluggish and mentally maybe fighting some demons. “I started trying to play better, the first set was not me at all. I knew I had to get better. I just tried to play my game.” Williams has now won 10 straight matches on clay, a run which took in the title in Charleston last month. The reward for her latest win is a last-eight clash with second seed Maria Sharapova. The Russian, a recent winner in Stuttgart, advanced after opponent Lucie Safarova withdrew before their clash through illness.
Fourth seed Agnieszka Radwanska also progressed to the next round, beating Roberta Vinci, of Italy, 7-6 (7/1) 6-4. Qualifier Lucie Hradecka, who accounted for third seed Petra Kvitova on Wednesday, continued her run with a 6-2 7-6 (7/5) success over Ekaterina Makarova to reach the quarter-finals.