Shvedova taken to three sets by Yaroslav Shvedova . three -time champion will next face Yaroslav Shvedova . Shvedova took every point in sixth set in beating Yaroslav Shvedova . Defending champion Petra Kvitova eases through .
Serena Williams taken to three sets by Zheng Jie . Four-time champion will next face Yaroslav Shvedova . Shvedova took every point in first set in beating Sara Errani . Defending champion Petra Kvitova eases through .