Sixth-seeded Andrea Petkovic advanced to the second round of the Qatar Open with a 6-7 (5), 6-3, 6-2 win over Belgian qualifier Kirsten Flipkens on Tuesday.
Venus Williams beat Agnieszka Radwanska on Thursday for the second time this year to advance to the Qatar Open semifinals, where she will meet two-time champion Victoria Azarenka.
Williams, who beat Radwanska to reach the Australian Open quarterfinals last month, won 6-4, 1-6, 6-3. It was the third time in four days that Williams had gone the distance for a three-set win.