Boston Red Sox’s Mookie Betts reacts in front of Toronto Blue Jays’ Russell Martin, left, after hitting a grand slam during the fourth inning of a baseball game in Boston, Thursday, July 12, 2018. (AP Photo/Michael Dwyer)

BOSTON (AP) — Mookie Betts fouled off seven pitches before hitting a grand slam that helped the Boston Red Sox beat the Toronto Blue Jays 6-4 on Thursday night, extending their winning streak to 10 games.

Betts added an RBI single in the seventh inning and went 2 for 4, increasing the top batting average in the majors to .352. He finished with five RBIs.

Boston has the longest current winning streak in the big leagues and hasn’t lost since getting routed by the Yankees 11-1 on July 1 in New York. At 66-29, the Red Sox are 37 games over .500 for the first time since 1949.

David Price (10-6) struck out eight over 6 2/3 innings for Boston, and Craig Kimbrel earned his 29th save.

Teoscar Hernandez hit a two-run homer in the first and Kendrys Morales had a solo homer for Toronto, which has lost four of five.

All-Star lefty J.A. Happ (10-6) started strong for Toronto, striking out six and holding Boston to two hits before running into trouble and some misfortune in the fourth. The Red Sox capitalized on a missed fly ball and a video review that erased what would have been the second out while scoring five runs — all unearned — before the inning ended.

Happ threw 46 pitches in the inning, 13 to Betts as he fouled off a string of five straight and caught a break when a popup bounced out of first baseman Justin Smoak’s glove after he ran it down in foul territory and attempted an over-the-shoulder catch. Betts worked Happ to a full count, then cleared the bases with a shot that sailed over the Green Monster.

Happ loaded the bases with a walk to No. 9 hitter Jackie Bradley Jr., who was batting .202. Happ also threw a wild pitch while walking Bradley in an inning that was extended when Boston successfully challenged a force at second on a fielder’s choice.

Price was booed loudly in the first after Hernandez’s two-run homer soared deep into the center-field seats, but didn’t allow another run until Morales led off the seventh with another shot to center that pulled the Blue Jays to 5-3. Price left to a standing ovation after allowing three runs and six hits.

Smoak hit an RBI double on a drive to center in the eighth, when a fan in the front row interfered with the ball and Randal Grichuk scored to pull the Blue Jays to 6-4.

TRAINER’S ROOM

Red Sox: 1B Steve Pearce exited after the second inning, when he was hit on the left ankle by a pitch from Happ. Pearce needed several minutes before going to first base and was replaced by Blake Swihart in the top of the third.

UP NEXT

Blue Jays: LHP Ryan Borucki (0-1, 2.25 ERA) gets his fourth career start after a no-decision Sunday, when he held the New York Yankees to one run and seven hits over seven innings.

Red Sox: RHP Rick Porcello (11-3, 3.58) has won three of four starts and already matched his victory total from last season.