Brandon Moss hit an RBI single in the bottom of the ninth and Coco Crisp followed with a game-winning sacrifice fly to lift the Oakland Athletics over the Boston Red Sox, 3-2, in the middle test of a three-game series.
Crisp also hit a solo home run as Oakland won its third straight game.
Jerry Blevins (2-0) tossed 1 2/3 innings of scoreless relief to earn the win. Bartolo Colon returned from the disabled list and allowed two runs -- one earned -- on five hits and a walk in a six-inning start for the A's. He had been sidelined since suffering an oblique injury on June 17.
"He didn't have the best command of his two-seamer so he found something else to get him through the game," said A's manager Bob Melvin of Colon. "What he did for us too was big in the win."
Alfredo Aceves (0-6) gave up the deciding runs for Boston, which lost for the fourth time in six games.
Aceves' fourth blown save spoiled a strong start by Jon Lester, who yielded one run on four hits and a walk while striking out nine over 6 2/3 innings.
"You gotta tip your hat to those guys. They had a good plan in the ninth and executed it," remarked Lester. "It's just one of those nights that they had the momentum going into the ninth and we didn't and it is what it is."
Aceves entered for the ninth and immediately gave up a base hit to Chris Carter. Two batters later, Cliff Pennington slapped a base hit to shallow center field to place the tying run on second base.
Moss followed with a line drive up the middle to plate Carter. On the play, Red Sox center fielder Ryan Kalish had the ball kick off the heel of his glove, allowing Pennington to advance to third on the error.
Crisp then fouled off three straight balls before lifting a ball to right- center field and Pennington easily cruised home on the sacrifice fly for the deciding run.
Oakland jumped out to the early lead when Crisp led off the bottom of the first inning with a blast over the left-field wall, but Boston answered in the second with Jarrod Saltalamacchia's two-out home run to right to make it a 1-1 game.
The Red Sox took the lead in the fourth inning when David Ortiz singled, advanced to third on Adrian Gonzalez's two-out base hit and came home on an error by Carter on a hard grounder off the bat of Saltalamacchia.
Kurt Suzuki's two-out single in the fifth inning snapped a string of 12 straight retired batters by Lester, but Crisp followed with an inning-ending grounder to third.
Oakland would only record one more hit against Lester from there, a one-out single by Carter in the seventh inning. However, Vicente Padilla entered in relief after Lester struck out Brandon Inge and fanned Seth Smith to end the inning.
Padilla returned for the eighth and after Suzuki reached on an error by Mike Aviles to start the inning, Crisp singled and Josh Reddick was issued an intentional walk following a Jemile Weeks sacrifice bunt to load the bases with one out.
Oakland would fail to capitalize on the opportunity, though, as Padilla struck out both Yoenis Cespedes and Jonny Gomes to quell the threat.
Meanwhile, Boston would strand a runner on third in the seventh and eighth innings, and a man on second in the ninth, leaving the door open for the A's in the bottom of the ninth.
Oakland designated pitcher Brian Fuentes for assignment to make room on the roster for Colon...The A's have now hit at least one home run in 14 straight games. It is their longest such streak since they also homered in 14 straight games from April 27-May 12, 2004...Gonzalez extended his hit streak to 14 games...Boston hit 0-for-8 with runners in scoring position and left seven men on base...Oakland went 1-for-4 with runners in scoring position and stranded eight.