Down 7-1 entering the bottom of the eighth, Boston rallied with a six-spot. Mike Carp, Jeremy Hazelbaker, Mauro Gomez, Jonathan Diaz and Jackie Bradley Jr. all had RBI hits for the Red Sox during the rally.
Orioles lefty Brian Matusz, who is trying to earn a rotation spot, wasn't unhittable, but he still got the job done. Over five innings, Matusz scattered six hits and a run, walking one and striking out two.
"For me, I have the mentality of wanting to build up pitches and innings and be a starter this year, and that's my mentality and taking advantage of the opportunity when [manager Buck Showalter] gives me the ball."
Would Matusz be disappointed if he doesn't land a starting job?
"You know what? That's really not on my mind right now," said Matusz. "My focus is just taking care of working out in the weight room … staying on my cuff program and just getting stronger, staying in good shape, keep competing and let those things fall into place."
Ryan Dempster continued to get stretched out for the Red Sox, giving up six hits and three runs over five innings. The righty walked two and struck out one.
"I got extended again," Dempster said. "I made a couple of mistakes ahead in the count, but I'm feeling better and better and I felt stronger today. Next time out, just get a little further. Things are coming together nice."
Orioles leadoff man Brian Roberts had a hit, a run, a stolen base and a walk. Third baseman Manny Machado belted two hits.
Will Middlebrooks had two hits for Boston, including a ground-rule double. Mike Napoli hit a first-inning sacrifice fly to get Boston on the scoreboard, but the lead was short-lived.
Trayvon Robinson hit a leadoff homer in the third, and then Roberts added an RBI single while Nate McLouth brought home another run with a run-scoring groundout.
Red Sox setup man Junichi Tazawa fired a scoreless sixth inning, striking out one.
Baltimore would tack on three more runs in the seventh off Daniel Bard, who hadn't allowed any in his previous five relief appearances. Jason Pridie made it 4-1 with an RBI groundout and then Ryan Flaherty added a two-run single.
Orioles reliever Kevin Gausman followed Matusz and fired two shutout frames of relief. The righty allowed just one hit and fanned three batters.
Up next: Left-hander Felix Doubront will take the ball for Wednesday afternoon's 1:05 ET game against the Yankees on MLB.TV. Key relievers Andrew Bailey, Andrew Miller and Joel Hanrahan are also slated to pitch. Bradley, Jose Iglesias, Ryan Sweeney and Daniel Nava will be among the position players making the trip to Tampa.