The Red Sox had a chance to win in the ninth when they loaded the bases with one out on a single by Brock Holt, a double by Dustin Pedroia and an intentional walk to David Ortiz. One run scored on Mike Napoli's groundout to second, but Mike Carp grounded out to first as Tommy Hunter escaped with his fifth save.
The game began at 11:09 a.m., about an hour before Meb Keflezighi crossed the Boston Marathon finish line just over a mile away as the first American man to win the race since Greg Meyer in 1983. A long, loud cheer went up in Fenway Park when the result of the race was shown on the center field video screen.
A Red Sox win would have been a bonus and they had several chances.
Trailing 7-4, Napoli led off the eighth with his fourth homer of the year. Singles by Xander Bogaerts and Daniel Nava put runners at first and second with one out. But pinch-hitter Jonathan Herrera struck out as the runners took off and Bogaerts was tagged between second and third.
Wei-Yin Chen (3-1) and five relievers pitched well enough for Baltimore to gain a split of the four-game series.
The Orioles started the third with consecutive singles by Steve Lombardozzi, David Lough, Nick Markakis, Nelson Cruz and Chris Davis that produced three runs. Adam Jones drove in another on a forceout at second base before a run-scoring double by Steve Clevenger and an RBI single by Jonathan Schoop made it 6-0 and knocked Buchholz (0-2) out of the game.
Burke Badenhop came in and ended the inning by getting Ryan Flaherty to ground into a double play. Badenhop also got Cruz and Clevenger to hit into inning-ending double plays in the fourth and fifth.
Chen allowed just one hit, a single by Ortiz in the fourth, before the Red Sox scored three runs in the fifth. Bogaerts led off with a walk and took second on Nava's infield single. After David Ross grounded into a forceout at second, the next three batters drove in runs on a ground-rule double by Jackie Bradley Jr., a sacrifice fly by Holt and a double by Pedroia.
Ryan Webb replaced Chen to start the sixth and struck out the side.
In the seventh, Boston cut the lead to 6-4 on Ross' first homer then had a chance to go ahead after Holt singled and Pedroia walked. But Ortiz ended the threat by grounding out.
Flaherty's RBI single in the eighth made it 7-4.
NOTES: Marc Fucarile, who lost his right leg in last year's Boston Marathon bombing, threw out the ceremonial first pitch. He was married in Fenway Park last Thursday. ... Boston's jerseys had the word "BOSTON" on the front instead of the usual "RED SOX." ... The Red Sox send Jon Lester (2-2) to the mound Tuesday night for the start of a three-game home series against the Yankees. Masahiro Tanaka (2-0) pitches for New York. The Orioles will start Miguel Gonzalez (1-1) against R.A. Dickey (1-3) of the Blue Jays in the opener of a three-game series at Toronto.