American fifth seed Sloane Stephens has crashed out in the fourth round of the Australian Open, succumbing to Russia's Anastasia Pavlyuchenkova in a late-night upset.
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The 2017 US Open champion came firing out of the gates but lost momentum, allowing the unseeded Pavlyuchenkova to fight back for a 6-7 (3-7) 6-3 6-3 victory.
Awaiting in the quarter-finals is American upstart Danielle Collins, who stunned three-time major winner Angelique Kerber in straight sets earlier on Sunday.
Australian hope Ashleigh Barty will face the winner of that match in the final four should she prevail in her quarter-final against Petra Kvitova.
Forced to watch on as Stefanos Tsitsipas downed Roger Federer in three hours and 45 minutes on Rod Laver Arena on Sunday night, Stephens and Pavlyuchenkova did not get underway on centre court until 11.23pm AEDT.
It didn't appear to phase Pavlyuchenkova, who blazed 46 winners and broke Stephens' serve seven times in an imposing display which wrapped up just before 2am.
"I heard somebody yawning during the match," Pavluchenkova joked.
"I'm sorry - I thought it was quite an exciting match, but anyway.
"I'm happy I stayed awake also. It was tough for us today."
The fourth-round women's action will continue on Monday when Elina Svitolina faces America's Madison Keys on Margaret Court Arena, followed by reigning US Open champion Naomi Osaka taking on Anastasija Sevastova.
World No.1 Simona Halep's clash with 23-time major winner Serena Williams headlines the night session on Rod Laver Arena, with the winner set to take on either Garbine Muguruza or Karolina Pliskova in the quarter-finals.
Australian Associated Press
