Auger-Aliassime handed Djokovic his first loss since May with a 6-3, 7-6(3) victory over the Team Europe superstar at the O2 Arena in London.
Team World leads 10-8 in the Ryder Cup-style competition and must win one of the final two matches in order to claim the trophy.
France Tiafoe of the United States may win the championship if he defeats Stefanos Tsitsipas of Team Europe.
A victory for Tsitsipas would set up a winner-take-all match between Casper Ruud and Taylor Fritz of Team World.
Saturday marked Djokovic’s first victory in two months, as the Wimbledon winner defeated Tiafoe in straight sets.
On Saturday, the 21-time grand slam champion, who missed the last US Open owing to his lack of vaccination, also teamed up with Matteo Berrettini to win a doubles match.
When he broke in the opening game of the first set against Auger-Aliassime, Djokovic had a chance to continue his impressive comeback.
Auger-Aliassime responded with a break of his own to square the score at 2-2.
Auger-Aliassime won the first set by serving it out after refusing to let Djokovic dictate play from the baseline.
Both players broke serve once in the second set, necessitating a tie-break that Auger-Aliassime dominated Djokovic in with some powerful groundstrokes.
It was Djokovic’s first loss since falling to Rafael Nadal in the quarterfinals of the French Open.
“It is one of the most impressive performances of my career. Against these great champions, I’ve been close a few times, so it feels amazing to finally win “Auger-Aliassime said.
Auger-first-ever Aliassime’s victory over Djokovic was especially impressive given that he and Jack Sock had defeated Berrettini and Andy Murray 2-6, 6-3(8) in doubles earlier on Sunday.
Sunday’s matches scored for three points each, therefore Team World remained in contention despite Team Europe’s 8-4 advantage entering the final day of the three-day competition.
Team Europe required two victories from four battles to win the Laver Cup for the fifth time in a row, while Team World required three victories to secure their first championship.
Auger-Aliassime and Sock won the first of the essential three victories in doubles.
Two days after his tearful farewell to tennis, Roger Federer was back courtside with his Team Europe teammates as he begins his retirement.
Murray and Berrettini stormed through the first set with breaks in the third and seventh games, with Federer cheering them on.
But Auger-Aliassime and Sock fought back to win the second set and kept their cool in the opening “Laver Breaker” game to 10 points.