Adam Jones hit a three-run homer off of Darnell McDonald in the top of the 17th inning on Sunday and the Orioles outlasted the Red Sox, 9-6, to sweep a three-game series.
McDonald (0-1), an outfielder, entered the game as a pinch-runner in the eighth inning and scored the tying run, then took the mound in the 17th in support of a spent Red Sox bullpen.
"I really focused on just trying to come in and throw strikes," McDonald said. "Our bullpen has been doing a heck of a job for us and you want to come in and pick them up, but unfortunately we weren't able to do it today."
Baltimore, which has won five games in a row and 11 of 13 overall, took advantage. J.J. Hardy doubled and Nick Markakis walked in front of Jones, who belted a 1-1 offering high over the wall in left.
Chris Davis (1-0) went 0-for-8 with five strikeouts as a designated hitter before tossing two scoreless innings of relief to earn the first win of his career.
"I'd like to see somebody top that one team-wise," Orioles manager Buck Showalter said of Davis' effort on the mound. "I think everybody made a contribution. Davis had about as bad of a day as you can have at the plate, but ended up being the star of the game. It's hard to believe."
The Red Sox nearly won the marathon in the 16th inning when Marlon Byrd reached on an error by third baseman Wilson Betemit and Mike Aviles followed with a deep fly to center off of Davis. The ball fell in for a double but Byrd was thrown out at the plate by Hardy, who hit two home runs earlier in the game.
Will Middlebrooks, who made his major league debut on Wednesday, hit a game- tying grand slam in the fifth inning for Boston, which has lost five straight overall and 10 of its last 11 games at Fenway Park.
Middlebrooks came to the plate facing a 5-1 deficit in the fifth. The Red Sox had loaded the bases in front of him on singles by David Ortiz and Cody Ross and a walk to Jarrod Saltalamacchia. The rookie third baseman then turned on the first pitch from Orioles starter Tommy Hunter and sent it over the wall in left for his first career home run.
Baltimore regained the lead in the eighth when Jones singled off of reliever Vicente Padilla, stole second, moved to third on an overthrow and scored on Mark Reynolds' double.
Ortiz doubled in the home half and the pinch-running McDonald moved to third on a groundout before scoring the tying run on Saltalamacchia's sac fly.
Boston's first run came in the bottom of the fourth, when Aviles doubled and then scored on Ryan Sweeney's single, but Baltimore had already pushed five across runs by that point.
Hardy hit solo homers in the first and third innings before Robert Andino struck in the fourth. After walks to Matt Wieters and Reynolds, Nick Johnson hit a fly ball off the base of the wall in center field. Wieters was held at third base on the play and Johnson, caught between first and second, was retired for the second out of the inning. Andino, though, followed with a shot over the wall in left for a 5-0 lead.
Davis is the first position player from the American League to win a game since 1968...Clay Buchholz started for Boston and allowed five runs in 3 2/3 innings. He has given up at least five earned runs in each of his last six starts...Middlebrooks missed Saturday's game with cramping in his left hamstring...Tommy Hunter started for Baltimore and gave up five runs in 4 1/3 innings.