Daniel Nava's three-run homer in the seventh inning backed seven scoreless frames by Clay Buchholz, as Boston downed Baltimore, 3-1, in the opener of a three-game set from Fenway Park.
Buchholz (2-0) allowed three hits and walked four with eight strikeouts for the Red Sox, who were coming off a series win in Toronto over the weekend.
"He had very good stuff today," Red Sox manager John Farrell said of Buchholz. "He threw seven solid innings."
Joel Hanrahan earned his third save, but served up an Adam Jones homer in the ninth.
Wei-Yin Chen (0-1) yielded five hits and three runs over 6 1/3 innings for the Orioles, who have lost three in a row since starting the year with three wins in four outings.
"It's seven games into the season," Jones said. "It's not like we just got blown out. We got beat."
Dustin Pedroia began the seventh with an infield hit, then Mike Napoli's double put two in scoring position. Two batters later, Nava launched a ball over the Green Monster for a 3-0 game and to send Chen to the bench.
Andrew Bailey then turned in a scoreless eighth for the hosts.
Jones began the ninth with a blast to left, then Hanrahan retired the next two batters before a J.J. Hardy double prolonged the contest. Ryan Flaherty, however, fouled out to third to end the contest.
The O's put two on with two down in the third and couldn't score, then saw Matt Wieters work a leadoff walk in the seventh and move up on a groundout before being silenced once more.
The Sox didn't see a runner advance past first base in their first six turns at the plate.
Baltimore won 13 of 18 games in the season series last year, including seven of nine in Boston ... The Red Sox are one of only four MLB teams not to commit an error thus far, and their seven errorless games to start the season set a new record which had not been eclipsed since they went six straight in 1957 without a blunder ... Boston announced that John Lackey will not make his next scheduled start due to inflammation in his right biceps, which forced him out of last Saturday's start in Toronto.