Williams sisters in US Open showdown
![Williams sisters in US Open showdown](http://www.timeslive.co.za/Feeds/2015/09/07/1238345_1021651.jpg/ALTERNATES/crop_80x80/1238345_1021651.jpg)
Serena Williams, chasing a calendar Grand Slam, on Sunday advanced to a dramatic US Open quarterfinal showdown with sister Venus while a concussion forced Canada's Eugenie Bouch-ard out of the tournament.
Serena Williams, chasing a calendar Grand Slam, on Sunday advanced to a dramatic US Open quarterfinal showdown with sister Venus while a concussion forced Canada's Eugenie Bouch-ard out of the tournament.