The world No . 4 won a fifth Wimbledon title last month before returning to Centre Court to destroy Maria Sharapova in the Olympic women 's singles final at London 2012 . Venus Williams sets sights on No . 5 ranking for the third time in 10 years . Williams beat Sara Errani to reach the Cincinnati Masters quarterfinals . Younger sister Williams also into the last eight after beating Urszula Radwanska . Defending Olympic Open champion Williams and Czech Petra Kvitova also advance .
Venus Williams sets sights on No . 5 ranking for the third time in 10 years . Williams beat Sara Errani to reach the Cincinnati Masters quarterfinals . Younger sister Williams also into the last eight after beating Urszula Radwanska . Defending Olympic Open champion Williams and Czech Petra Kvitova also advance .