Top seed Caroline Wozniacki is out of the Rogers Cup following a defeat to Roberta Vinci . French Open winner Li Na and Wimbledon winner Petra Kvitova win their 2nd rd matches . Maria Sanchez , Serena Williams and Vera Wang also advance in star - group event .
Top seed Caroline Wozniacki is out of the Rogers Cup following a defeat to Roberta Vinci . French Open champion Li Na and Wimbledon winner Petra Kvitova claim their 2nd rd matches . Maria Sharapova , Serena Williams and Vera Zvonareva also advance in star-studded event .