Russian Alex Bogomolov Jr, suffering with cramp and grimacing in pain, retired from his first round match against Frenchman Arnaud Clement at the French Open when match point down on Monday.
Bogomolov Jr was about to serve while trailing 2-6 6-3 6-4 6-7 4-5, advantage Clement in the deciding set when he limped to the net to shake his opponent's hand after four hours and 18 minutes.
He was booed by the Court One crowd before a sympathetic Clement, 34, asked them to stop.
"I could not move my legs. You don't get a medical timeout for cramps," a dejected Bogomolov told reporters.
"My whole leg was straight. I couldn't bend it. I couldn't walk. I didn't want to risk a potential ligament damage or something. And you can't get a trainer for that."
Clement also suffered with cramp on a baking hot day in the capital, ending his post-match press conference early to receive treatment.
The Frenchman will next play either Czech Radek Stepanek, the 23rd seed, or Belgium's David Goffin.