VIDEO: Serena Williams hits her own face in Australian Open victory

Serena Williams once again battled through the pain barrier to advance at the Australian Open on Thursday, but this time the American third seed's injury was entirely self-inflicted.

After rolling an ankle during her first round win the 15-time grand slam champion hit herself in the face with her racket as she brushed aside Spanish teenager Garbine Muguruza 6-2 6-0.
It left her anxiously checking her mouth for damage.