World number four Simona Halep was knocked out in the first round of the Australian Open in straight sets by American Shelby Rogers on Monday.
The Romanian lost 6-3 6-1 to the 24-year-old, ranked 48 places below her.
Rogers, beaten in the first round in her only previous Australian Open appearance in 2015, saw off the 25-year-old in one hour and 15 minutes.
It is the second successive year Halep, who called for medical attention, has lost in the first round in Melbourne.
Rogers will face the winner of the match between Australia's Ashleigh Barty and Germany's Annika Beck in round two.