Adrian Gonzalez homered and drove in four runs and Felix Doubront threw six solid innings to earn Boston their second win in this four-game series, which concludes on Thursday night.
Mark Teixeira smashed a two-run homer in a four-run first inning for New York as the AL East-leading Yankees sealed a sweep of Toronto with a rain-shortened 6-0 win over the Blue Jays in 6 1/2 innings.
Cleveland overcame the Tampa Bay Rays 10-6, Carlos Santana hitting a three-run homer in the Indians' five-run seventh inning, while Brandon Hicks' first career homer in the bottom of the ninth inning secured a 4-3 win for the Oakland Athletics against the Texas Rangers.
Elsewhere in the American League, the Detroit Tigers were 7-2 winners against the Los Angeles Angels, the Kansas City Royals squeezed past the Seattle Mariners 8-7 and the Baltimore Orioles prevailed 2-1 against the Minnesota Twins.
Jordan Zimmermann threw six scoreless innings and Adam LaRoche had a two-run homer as the National League East-leading Washington Nationals edged New York 4-3 - a sixth straight defeat for the Mets.
Jason Kubel marked his return to the Arizona line-up after a hamstring injury with a pair of home runs to lift the Diamondbacks to a 7-1 triumph over Cincinnati.
The result dropped the Reds into a first-place tie in the NL Central alongside Pittsburgh. The Pirates overcame the Colorado Rockies 9-6, Garrett Jones' three-run shot in the third kickstarting the rally.
Matt Kemp's two-run, walk-off homer in the 12th inning earned the Los Angeles Dodgers a 5-3 win against the Philadelphia Phillies, while the NL West-leading San Francisco Giants clinched their fifth straight win with a 9-4 success against the Atlanta Braves
In other National League games, the San Diego Padres toppled the Houston Astros 8-4, the Chicago Cubs defeated the Miami Marlins 5-1 and the Milwaukee Brewers saw off the St Louis Cardinals 4-3.