Boston pushed across a pair of runs in the seventh against Gregg on an Adrian Gonzalez sac fly and a Will Middlebrooks single to break a 5-5 tie before adding a run against Troy Patton in the eighth. That carried the Red Sox to an 8-6 win over the O's at Camden Yards.
Boston rallied from a 5-2 deficit to improve to 9-2 over its last 11 games, winning for the first time this year in four games against the Orioles.
The Birds were down 2-0 and then scored four in the last of the third against Clay Buchholz in an inning that included three singles and three walks, one of which was with the bases loaded to Xavier Avery. An inning later, Chris Davis hit a solo homer. It was his first since May 1 and gave the O's a 5-2 lead.
But Tommy Hunter could not hold that edge as the Red Sox scored three in the sixth to tie in an inning that included a David Ortiz solo homer onto Eutaw Street and a Hunter balk that forced a run across.
Entering this series, the Orioles were 13-7 on the season against the AL East and 23-12 against the East since last September 7.
The Orioles fall to 12-10 at home, 13-7 in May and 27-16 overall. In Game 2 of the series tomorrow night, Brian Matusz (3-4, 5.36 ERA) pitches against Boston's Felix Doubront (4-1, 4.09 ERA).