Jose Bautista homered twice and drove in three runs, leading Toronto over Boston by a 6-2 count in the third edition of a four-game set from Fenway Park.
"I had a good day in the cage and had a good batting practice, so I felt more in rhythm than in days past," Bautista said. "When I swung I didn't miss, so I can say it was a good day."
Adam Lind added three hits and an RBI, while Jose Reyes ended with two hits, scored twice and drove in a run for the Blue Jays, who had dropped the first two in the series.
Steve Delabar (5-1) gave up two hits and struck out four in 1 2/3 relief innings for the win. That performance backed up six scoreless frames from starter Esmil Rogers, who allowed six hits and one walk while fanning six.
Shane Victorino posted two hits and drove in both runs for the Red Sox, while Junichi Tazawa (4-3) was tagged with the loss after giving up Bautista's go- ahead blast in the eighth.
Reyes greeted Tazawa with a single to begin the deciding frame, then Bautista launched his second homer of the game, this one to left center, which provided a 4-2 advantage for Toronto.
"He's a very good player," admitted Red Sox manager John Farrell. "Certainly capable of hitting it out of the ballpark every time he steps into the box."
J.P. Arencibia singled with one out in the ninth and advanced on Mike Napoli's fielding error, then scored on Reyes' single down the left-field line for a three-run Blue Jays bulge. Sox third baseman Jonathan Diaz then booted a Bautista grounder, allowing Reyes to score, but Bautista was out at third to end the inning.
Neil Wagner worked around a walk to post a scoreless home ninth.
Lind's two-out RBI single in the first put Toronto on the board. Edwin Encarnacion, who reached on a fielder's choice and moved to second when Bautista was erased in a rundown between third and home, scored on the hit.
After the Sox couldn't bring home a runner from second in the home fifth, Bautista cleared the Green Monster with plenty of room to spare to start the sixth.
Victorino, who doubled to start the home portion, was thrown out by Bautista when trying to score on a Dustin Pedroia base hit. David Ortiz also singled, but Rogers left two on after fanning Napoli and Daniel Nava in succession.
"It was a great throw. We're going to be aggressive and stay aggressive," Victorino said of the decision to send him home. "We lost the game, but credit us for showing resiliency and coming back to tie."
Boston managed to tied the score in the seventh. Facing Darren Oliver, Jarrod Saltalamacchia singled, then Jose Iglesias bunted for a hit. Diaz then reached on a squeeze attempt which erased Saltalamacchia at home, and after Steve Delabar entered the game, Ellsbury singled to load the bases. Victorino followed with a base hit to score Iglesias and Diaz.
Toronto won for the 16th time in its last 22 games to reach the .500 mark at 40-40 ... Bautista posted his fourth multi-homer effort of the season and first since June 10 against the White Sox, also recording his 21st career game with at least two longballs ... Boston starter Felix Doubront allowed five hits and two runs with six strikeouts and three walks over 6 1/3 innings ... The Red Sox failed in their bid to become the first team in the majors to win 50 games ... Prior to the contest, the Red Sox selected the contract of Diaz from Triple-A Pawtucket, designated pitcher Clayton Mortensen for assignment and signed pitcher Teddy Stankiewicz.