Reigning defending champion the latest top seed to fall . World No . 4 loses in straight sets to world No . 145 Aleksandra Krunic . Serena Williams through to last 16 after win over Vera Lepchenko . Andy Murray and Novak Djokovic through to last 16 in men 's draw .
Reigning Wimbledon champion the latest top seed to fall . World No . 4 loses in straight sets to world No . 145 Aleksandra Krunic . Serena Williams through to last 16 following win over Varvara Lepchenko . Andy Murray and Novak Djokovic through to last 16 in men 's draw .