MELBOURNE, Feb 5 (Reuters) - Serena Williams (NYSE:WMB) 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"Serena Williams has withdrawn from the Yarra Valley Classic singles draw due to a right shoulder injury," the women's tour said on Twitter.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."