Red Sox 4, Yankees 3: Jacoby Ellsbury celebrated his 29th birthday by driving in the winning run with a walk-off single in the ninth as host Boston snapped a four-game slide.

Ellsbury finished with four hits, two RBIs, one run scored and a stolen base, and Dustin Pedroia homered as the Red Sox put a dent in rival New York’s playoff chances. The Yankees dropped back into a tie for first place in the American League East with the Baltimore Orioles.

Pedro Ciriaco began the rally with a one-out single and Mike Aviles followed with an infield hit. Ellsbury came up next and hooked a 1-1 changeup from David Robertson (1-7) through the right side. Ciriaco slid in just ahead of Ichiro Suzuki’s throw.

Andrew Bailey (1-0) picked up the win in relief.

The Yankees grabbed a run in the first on Robinson Cano’s RBI groundout, but left the bases loaded in that frame and left runners in scoring position in four of the first five frames.

That allowed the Red Sox to jump back into the game in the third. Ciriaco led off with a double and scored the tying run on Ellsbury’s RBI single. Ellsbury stole second and came home on Pedroia’s single to give Boston a 2-1 edge.

New York finally capitalized on a scoring opportunity in the sixth to re-take the lead. Curtis Granderson drew a leadoff walk against Jon Lester and Andruw Jones followed with a single before both runners moved up on a sacrifice.

Derek Jeter ended Lester’s night by fisting a 3-2 pitch down the right-field line. The ball bounced up into the stands hugging the foul line and scored both on the ground-rule double.

Pedroia made sure Hiroki Kuroda would not earn a win, responding in the bottom of the sixth with a solo blast - his 15th - into the first row of the “Green Monster” seats in left.

GAME NOTEBOOK: Lester broke Boston’s record for strikeouts by a left-handed pitcher, previously held by Bruce Hurst at 1,043, when he punched out Steve Pearce to end the fifth. Lester is up to 1,044 after striking out five on Tuesday. The left-hander also issued seven walks and was charged with three runs on five hits in 5 1/3 innings. … Red Sox LHP Franklin Morales had an MRI on his ailing left shoulder. He is likely out for the season. … Yankees RHP Ivan Nova threw a simulated game on Tuesday afternoon and could make his return to the rotation this weekend. … New York recalled OF Melky Mesa.