Novak Djokovic 6-3, 7-6(3) to put Team World within sight of their first ever victory over Team Europe in the Laver Cup on Sunday.
Auger-Aliassime produced a masterful performance at a packed O2 Arena, holding off a Djokovic comeback in the second set to clinch Team World's second victory of the day.
Earlier, Auger-Aliassime and Jack Sock had come from a set down to beat Andy Murray and Matteo Berrettini 2-6 6-3 10-8. Europe begun the day with an 8-4 lead going into the last four matches of the weekend but with a win rewarded by three points on the final day there was the potential for a big swing.
Serbian Djokovic had been imperious the previous evening on his return to action for the first time since winning Wimbledon in July to reach 21 Grand Slam titles.