Felix Auger-Aliassime stunned Novak Djokovic to put Team World on the brink of winning the Laver Cup for the first time on Sunday.
Auger-Aliassime handed Djokovic his first defeat since May as the Canadian youngster powered to a 6-3, 7-6 (7/3) victory over the Team Europe star at London's O2 Arena.
Team World lead 10-8 in the Ryder Cup-style tournament and need one win from the last two matches to lift the trophy.
France Tiafoe of the United States can clinch the title if he beats Team Europe's Stefanos Tsitsipas.
A victory for Tsitsipas would set the stage for a winner-takes-all decider between Casper Ruud and Team World's Taylor Fritz.
Djokovic had won his first match for two months on Saturday when the Wimbledon champion defeated Tiafoe in straight sets.
The 21-time Grand Slam winner, who missed the recent US Open due to his unvaccinated status, also joined forced with Matteo Berrettini to win a doubles match on Saturday.
"It's one of the best performances of my career. I've been close a few times against these great champions, so it feels to great to get a win like this," Auger-Aliassime said.