Boston Red Sox’s Mookie Betts doubles in the fifth inning of a baseball game against the Baltimore Orioles in Baltimore, Monday, Sept. 18, 2017. Xander Bogaerts, Brock Holt and Andrew Benintendi scored on the play.

BALTIMORE — Andrew Benintendi hit a two-run single in the 11th inning, Mookie Betts had four RBIs and the Boston Red Sox beat the Baltimore Orioles 10-8 Monday night for their ninth win in 12 games.

Xander Bogaerts homered and scored three runs for the Red Sox, who maintained their three-game lead over the second-place Yankees in the AL East and reduced to four their magic number for clinching a playoff berth.

Boston erased a five-run deficit with a six-run fifth inning and needed 10 pitchers to beat a skidding Orioles team that has now lost 10 of 12.

After three walks — one intentional — off Miguel Castro (3-2) loaded the bases in the 11th, Benintendi grounded a single past diving second baseman Jonathan Schoop to give Boston its major-league leading 14th extra-inning win against three defeats.

Matt Barnes (7-3) pitched the 10th and Carson Smith got three outs for his first save.

Red Sox second baseman Dustin Pedroia left in the fourth inning after being struck in the face by a foul ball he chopped off the plate. The team described the injury as a bruised nose and listed his availability as day to day.

It was the second freak injury Pedroia sustained at Camden Yards this season. On April 21, the All-Star was spiked on a late slide by Manny Machado, a play that created bad blood between the teams into May.

Baltimore built a 5-0 lead against Doug Fister over the first three innings, taking advantage of five walks and getting a two-run double from rookie Austin Hays.

After Betts hit an RBI double in the fourth, Adam Jones countered with a run-scoring single in the bottom half. But the 6-1 advantage vanished in the fifth under a torrent of six hits against Dylan Bundy and two Baltimore relievers.

The key blows in the six-run inning were a two-run double by Brock Holt — Pedroia’s replacement — and a bases-loaded double by Betts that scored all three runners.

Pedro Alvarez homered in the bottom half and Tim Beckham put Baltimore back in front with a two-out RBI double.

The see-saw leveled in the seventh when Bogaerts homered off Donnie Hart to make it 8-all.

TRAINER’S ROOM

Red Sox: Betts was in the starting lineup despite hurting his thumb in two places Sunday. … DH Hanley Ramirez (left arm soreness) did not start but appeared as a pinch-hitter in the ninth. … 2B Eduardo Nunez will test his sore right knee running the bases Wednesday. Manager John Farrell said: “Wednesday will be a good test in terms of where he is at.”

UP NEXT

Red Sox: LHP Drew Pomeranz (16-5, 3.28 ERA) looks to keep his outstanding season going in his fourth start of the year against Baltimore. Pomeranz was 25-36 lifetime before this season.

Orioles: Kevin Gausman (11-10, 4.83 ERA) makes his 32nd start of the year, the fourth against Boston. He’s 1-2 with a 3.86 ERA against the Red Sox in 2017.