BOSTON — Jason Bay and J.D. Drew homered and the Boston Red Sox overcame a seven-run deficit to defeat the Baltimore Orioles 10-8 on Friday night.

Bay broke an 8-8 tie with a sacrifice fly off Danys Baez (0-1) in the eighth inning to score Dustin Pedroia. Bay was 1-for-3 with three RBIs and two runs scored while Pedroia finished 3-for-4.

Mike Lowell's RBI single later in the inning scored Kevin Youkilis to give Boston a 10-8 lead.

The Orioles threatened in the eighth. Hideki Okajima relieved Ramon Ramirez (1-0), who was one of five Red Sox relievers to pitch six scoreless innings in relief of Brad Penny, after he allowed singles by Brian Roberts and Adam Jones.

The runners moved to second and third after Nick Markakis flied out, but Okajima struck out Aubrey Huff swinging to end the inning. Markakis was 2-for 4 with five RBIs, including a grand slam.

Jonathan Papelbon pitched the ninth for his third save.

The Orioles raced out to a 7-0 lead in the second inning, keyed by Markakis' grand slam.

The Red Sox rallied for four in the bottom of the inning. Drew walked and Bay homered into the Orioles' bullpen off Orioles starter Jeremy Guthrie. The Red Sox added two more in the inning on an RBI single by Jacoby Ellsbury and David Ortiz's sacrifice fly.

Drew homered to lead off the third, cutting it to 7-5.

Markakis made it 8-5 with an RBI double in the fourth.

But Drew keyed the Red Sox again, this time with a two-out triple in the fifth. Guthrie walked Bay and Lowell to load the bases.

Huff then committed an error on a grounder by Jason Varitek, as Drew scored Boston's sixth run. Nick Green followed with a two-run double, tying the game 8-8.

Penny, making his first start at Fenway for the Red Sox, struggled to get the ball over the plate, including a 40-pitch second inning in which he twice walked in a run on four pitches. He worked into the third inning, but was replaced by Manny Delcarmen after walking Adam Jones.

Penny lasted three innings, walking five and giving up eight earned runs. His ERA is 11.00

Delcarmen allowed Markakis' RBI double in the fourth. It was the only hit he allowed in 2·innings before giving way to Javier Lopez in the sixth.

Penny allowed the first four batters in the second to reach base, including a four-pitch walk to Ryan Freel, which gave the Orioles a 1-0 lead. Penny retired Cesar Izturis, but Brian Roberts singled and Jones walked on four pitches to give the Orioles a 3-0 lead.

Markakis then hit the second pitch from Penny over the center-field wall, giving the Orioles a 7-0 lead. It was his second homer of the season and the second grand slam of his career, the other was against Kansas City on April 13, 2007.

The seven runs were the most scored in an inning this season by the Orioles and the most allowed by the Red Sox.

Notes: Bay earned his 500th career RBI on his second-inning homer. ... Pumpsie Green threw out the first pitch. The Red Sox honored the former infielder on the occasion of the 50th anniversary of his breaking the color barrier for the team in 1959. ... Roberts, who started the season 6-for-6 with runners in scoring position, including his base hit in the second, had his streak snapped when he grounded out to Youkilis in the third inning. ... Izturis is 0-for-16 in the first four games of a seven-game trip. ... Youkilis and Bay have both reached safely in all 10 of Boston's games. ... The Orioles have lost all four of Guthrie's career starts at Fenway.