American tennis player CoCo Vandeweghe has shocked fans with a "petulant" act during a warm-up at a tournament in the US.
The former world No. 9 was playing her first match at the ITF competition in Landisville, Pennsylvania against Georgian Ekaterine Gorgodze.
Vandeweghe won the first set and appeared to be playing comfortably before she changed tack completely.
Down 3-4 in the second set, Vandeweghe seemed to blatantly throw in the towel, barely competing in points as Gorgodze easily levelled the match at one set all.
She didn't make an effort to chase down shots and also grabbed her leg, which was bothering her.
After the second set, Vandeweghe called for a medical time-out and play was suspended due to extreme heat.
"Coco was just about to call it a day when they said they've got to shut it down because of heat reasons," a commentator said.
But once the players returned to the court, the American was clearly bothered and didn't want to warm up again.
In bizarre scenes, Vandeweghe refused to give Gorgodze a legitimate warm up — not moving her feet, hitting casual forehand slices barely over the net and even swapping her racquet into her weaker left hand.
"This is unbelievable. Coco doesn't want to warm up," the commentator added.
"And she says if you're going to make me do it then I'm not going to move, I'm not going to do anything.
"I've never seen this in my life. This is wild. She's going to do just enough here just so she doesn't get in trouble."
Play was later suspended due to heavy rain, with Gorgodze leading 6-7 6-3 2-0, but fans and experts were left gobsmacked by Vandeweghe's bizarre display.
Now ranked 151st in the world, Vandeweghe's career has been riddled by injuries since she made the semi-finals of both the Australian Open and US Open in 2017.