Boston Red Sox's Jackie Bradley Jr. goes airborne toward home plate as he tries to beat the throw while scoring on the game-winning, two-run double by Mookie Betts during the ninth inning  against the St. Louis Cardinals in Boston, Wednesday. The Red Sox won 5-4.
Boston Red Sox's Jackie Bradley Jr. goes airborne toward home plate as he tries to beat the throw while scoring on the game-winning, two-run double by Mookie Betts during the ninth inning against the St. Louis Cardinals in Boston, Wednesday. The Red Sox won 5-4. Credit: ap

BOSTON — Mookie Betts finally had a pitch he could drive and the Boston Red Sox pulled out anther last at-bat win in Fenway Park.

Betts lined a two-run double off the Green Monster with two outs in the ninth inning, capping a three-run rally that lifted the Red Sox to a 5-4 win over the St. Louis Cardinals on Wednesday night.

Xander Bogaerts opened the ninth with a solo homer for the AL East-leading Red Sox, who won for the 12th time in 14 games and maintained their 4½-game lead over the second-place New York Yankees.

It was Boston’s eighth walk-off win in its last 19 victories at home.

Cardinals manager Mike Matheny was ejected by home plate umpire Chris Segal in a wild ninth inning. Trevor Rosenthal gave up Bogaerts’ homer into the Monster seats.

Zach Duke (0-1) struck out a batter and walked one before John Brebbia gave up Betts’ hit after he laid off a pair of tough sliders, with Jackie Bradley Jr. beating a relay home with a headfirst slide for the winning run as catcher Yadier Molina dropped the throw.

“It changed the whole at-bat. I was able to force him to throw a strike,” Betts said. “Anytime I get a strike, I’ve got a better chance to put good wood on it.”

Bradley didn’t see Molina drop the throw as he slid past the plate without touching it. He had to reach back after he stopped.

“I pulled my hand back completely to try and avoid the tag,” he said. “I knew I didn’t tag it at first. I didn’t pay attention whether he had the ball or not. I was just trying to tag the plate.”

Molina was arguing with Segal before Matheny came out.

“The fact that he was kind of going at it with our catcher, you hate to see it at that particular point of the game,” Matheny said. “But a lot of barking going on all game long.”

Kolten Wong had three hits, including an RBI single in St. Louis’ four-run second inning, and Lance Lynn held Boston’s offense down with six solid innings before the Red Sox rallied.

It was just the third loss in 11 games for the Cardinals, who were swept in the two-game series, their first visit to Fenway Park since the 2013 World Series.

Craig Kimbrel (5-0) pitched one hitless inning for the win.

Lynn allowed two runs and seven hits, walking and striking out three.

Eduardo Rodriguez gave up four runs and eight hits in 5 1/3 innings.

The Cardinals jumped ahead 4-0 when Wong and Matt Carpenter sandwiched RBI singles around Luke Voit’s run-scoring double. Wong scored on Christian Vazquez’s passed ball.

Vazquez scored on a throwing error in the third when Lynn fired the ball wildly past first on Eduardo Nunez’s infield hit. Betts added his sacrifice fly.