Curtis Granderson hit a walk-of home run in the 10th inning to lift the Blue Jays past the Red Sox 4-3 in Toronto.
Granderson also drove in two with a single and finished with three hits and three RBI.
The Red Sox tied the game in the ninth inning by scoring two runs off Blue Jays closer Roberto Osuna before Granderson went deep.
J.A.Happ struck out 10 over seven innings of one-run ball in a no-decision. Tyler Clippard got the win as Toronto snapped a two-game slide to move to 14-and-8.
Craig Kimbrel took the loss. The 17-and-5 Red Sox are on a three-game slide but still own the best record in the majors. Toronto is now three games back of Boston in the A-L East.