Serena Williams pulled out of a semi-final clash against World No. 1 Ashleigh Barty with a shoulder injury on Friday, days before the Australian Open, while Simona Halep and Sofia Kenin both crashed to defeat. 

Williams, 39, had ousted fellow American Danielle Collins 6-2, 4-6, 10-6 in the Yarra Valley Classic but withdrew from the tournament hours later despite showing no ill effects during the match. Barty now has a bye into the final where she will meet either two-time Grand Slam winner Garbine Muguruza or Marketa Vondrousova.