The Red Sox claimed all seven of their runs in an explosive second inning, capped by Dustin Pedroia's two-run blast, and restricted the visiting Blue Jays to just five hits in a controlled victory.
An impressive John Lester (8-4) pitched into the eighth inning to pick up the win but worryingly for Boston, he left the game with a right hip injury.
Boston remain 3 1/2 games clear in the division with an AL-leading 48-33 record while Toronto (39-39) stay rooted to the bottom of the East, 7 1/2 games adrift.
Elsewhere, Derek Holland pitched a complete game two-hitter to help his the Texas Rangers record a 2-0 shutout win over the New York Yankees.
It was the pitcher's first win over the Yankees after he allowed 39 earned runs in 39 innings against them in the past, and kept the Rangers (46-33) on top of the American League West.
The Yankees dropped to 42-36 after Rangers rookie Jurickson Profar accounted for both runs, coming home on an Ian Kinsler sacrifice fly before belting a home run over the right field wall.
The Los Angeles Angels were too strong for the host Detroit Tigers for the third game running, getting home 3-1 over 10 innings.
Albert Pujols' shot to center was just out of Austin Jackson's reach in the 10th, bringing in the tie-breaking run before Josh Hamilton padded the margin with a sacrifice fly.
The Angels improved to 36-43 but remain third in the AL West while the Tigers dropped to 42-35 but continue to lead the AL Central.
Arizona Diamondbacks pitcher Patrick Corbin's (9-0) 10th win eluded him once more with a fifth straight no-decision, but his side prevailed 3-2 in 11 innings over the Washington Nationals.
Didi Gregorius bunted in the go-ahead run to snap the 2-2 tie that had lasted from the sixth inning.
Arizona remain in control of the NL West at 42-36 with Washington falling to 39-39, now 5 1/2 games behind NL East leading Atlanta.
A two-run homer from Marlon Byrd in the top of the eighth helped the New York Mets (32-43) squeak by the Colorado Rockies (39-41) 3-2 in a make-up game from an April washout.
Baltimore (44-36) stayed within 3 1/2 games of the Red Sox with a 7-3 win over the Cleveland Indians (40-38), who now sit 2 1/2 games behind Detroit.
The Los Angeles Dodgers picked up their sixth win in a row with a 6-4 win over the Philadelphia Phillies (38-42) but remain at the bottom of the NL West with a 36-42 record.
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