Bautista finished 3-for-5 with two RBI and two runs scored, while Jose Reyes ripped a two-run single and scored once in support of Buehrle (8-1), who fanned five and allowed just two runs on seven hits without issuing a walk to become the first pitcher in the majors to reach eight wins.
Edwin Encarnacion and Brett Lawrie added an RBI apiece for the Blue Jays, who have won seven of their last eight games.
Xander Bogaerts smacked a solo homer and Jonny Gomes drove in a run for the Red Sox, who dropped their seventh straight tilt to wrap up a six-game homestand. Boston went winless on a homestand of at least six games for the first time since June 10-15, 1994.
Boston starter Jon Lester (4-6) was tagged for all seven runs on 10 hits over 6 1/3 innings to absorb the loss.