World No 2 Maria Sharapova has been ruled out of the Cincinnati Masters due to a right leg strain
Meanwhile, American player Venus Williamson has also withdrawn from the masters after suffering with virus.
Williamson was set to lock horns with Ana Ivanovic in the second round, who has now advanced to the third round by walkover.
Williamson had earlier secured 7-6, 6-4 win over opponent Zarina Diyasin the first round of the Cincinnati Masters.
