Intro:

Serena Williams and Agnieszka Radwanska advanced to the quarter-finals of the Western & Southern Open on Thursday (August 17) following respective wins over Urszula Radwanska and Sloane Stephens.

Script:

Top-seed Agnieszka Radwanska overcame an unexpected challenge from wild-card Sloane Stephens in the third round of the Southern & Western Open on Thursday.

Radwanska, who lost to Serena Williams in the Wimbledon final, took the first set 6-1.

But 19-year-old Stephens produced some aggressive tennis to level it at one set all.

However Radwanska's superiority shone through as the 23-year-old Pole reached the tournament's quarter-final for the first time.

Serena, joined her sister, Venus in the next round by beating Urszula Radwanska of Poland 6-4, 6-4.

Williams hasn't lost a set since her victory in the Wimbledon final against Radwanska.

Caroline Wozniacki dropped the first set of her third round match with Anastasia Pavlyuchenkova before rain suspended play.

The pair will return to the court on Friday, with the winner having to play Petra Kvitova in the quarter-finals later that evening.