Serena withdraws from Australian Open tuneup event with shoulder injury

Serena Williams pulled out of the Yarra Valley Classic on Friday with a right shoulder injury, few hours after her quarter-final victory in the Australian Open tuneup event.

Williams, the winner of 23 Grand Slam singles titles, had set up a mouth-watering semi-final clash against world number one Australian Ash Barty after defeating fellow American Danielle Collins 6-2, 4-6, (10-6) on Margaret Court Arena.

"Serena Williams has withdrawn from the Yarra Valley Classic singles draw due to a right shoulder injury," the women's tour said on Twitter.

"Ashleigh Barty advances to the final by walkover."