Vladimir Guerrero Jr. drove in three runs for the Blue Jays, who turned the game into a rout with a six-run fifth inning.
Toronto (57-89) has won two in a row after ending a seven-game skid. The Blue Jays will go for a sweep of the slumping Red Sox (76-70) — losers of five straight — on Thursday night.
Both teams used openers for the first two frames.
Toronto’s Wilmer Font gave up a single over his appearance before right-hander Trent Thornton (5-9) delivered a masterful five-inning effort. Thornton didn’t give up a hit, issued one walk and had seven strikeouts.
Boston lefty Bobby Poyner made his first big-league start before he was replaced by Trevor Kelley (0-1). The Blue Jays took advantage of some weak defence in the fourth inning to open the scoring.