A.J. Griffin stymied Boston's potent offense by firing eight outstanding innings, enabling the Oakland Athletics to get back on track with a 3-0 win over the Red Sox in a matchup of AL division leaders from the O.co Coliseum.
Griffin (8-6) scattered six hits and walked just one before turning things over to Grant Balfour, with the fiery closer finishing off the shutout and stopping his club's two-game skid that included a 4-2 setback in Friday's opener of this three-game series.
The duo received offensive support from Derek Norris, who broke a scoreless tie with a solo homer in the fifth inning, as well as RBI singles from Yoenis Cespedes and Coco Crisp later on.
Jon Lester (8-6) was charged with all three Oakland runs over an otherwise- solid 6 1/3 innings, but was handed his sixth loss in eight decisions due to his teammates' inability to come through in the clutch.
"The guy on the other side, you've got to tip your hat sometimes," said Lester. "He pitched better than me, that was the case tonight."
The Red Sox stranded eight baserunners, four of which were left in scoring position, and went 0-for-5 in such situations to have a four-game win streak halted.
Griffin's outing was very effective, albeit hardly stress-free. The Red Sox placed men on base in each of the right-hander's first six innings, but were unable to deliver the key hit on each occasion.
"He really made some in-game adjustments," said Oakland manager Bob Melvin. "Starts with his fastball, his curveball always plays into it with the speed of it to create the gap, and threw some good change-ups to the lefties."
Lester, on the other hand, had retired nine straight Oakland hitters until Norris scorched a line drive that just cleared the scoreboard in left center to break the scoreless deadlock with two outs in the bottom of the fifth.
The A's tacked on another run an inning afterward, with Josh Donaldson and Cespedes delivering back-to-back singles following a walk to Jed Lowrie to push the lead to 2-0.
Oakland furthered the margin in the seventh, putting the first two runners aboard on a Josh Reddick single and Norris drawing a walk against Lester. Two batters later, Crisp greeted reliever Junichi Tazawa with a base hit to right that allowed Reddick to trot home from third.
Boston's best scoring chance came in the top of the sixth, when David Ortiz reached on a throwing error by A's second baseman Grant Green and was moved to third on Daniel Nava's two-out single. Griffin came up with another big pitch, however, to get Jarrod Saltalamacchia to fly out and end the threat.
Griffin capped off his terrific effort by setting down the next six hitters before giving way to Balfour, who permitted a leadoff single to Mike Napoli in the ninth but nothing thereafter to extend his streak of consecutive saves to 43 dating back to last season.
Crisp's RBI was the 500th of his career ... The A's posted their 55th win of the season, the team's highest total prior to the All-Star break since 1975 ... Six of Norris' 12 career home runs have given Oakland a lead, with three of those shots breaking a tie score ... Lester fell to 1-6 over his last seven road starts, and 12 of his 15 homers allowed this season have come in visiting parks ... Napoli added a double in the fourth inning to extend his on-base streak in road games to 27, the longest active stretch among AL players ... Oakland improved to 35-14 when scoring first this season, while the Red Sox are 17-30 when giving up the game's first run.