OAKLAND, Calif. -- Every time he found himself in trouble, Athletics pitcher A.J. Griffin tried to channel teammate Bartolo Colon. Having seen Oakland's lone All-Star selection keep his calm all season no matter the circumstances, Griffin simply followed suit.
Even when he lost a chance at a complete game.
Griffin (8-6) wasn't crisp but still went eight scoreless innings to remain unbeaten in his last five starts. The Oakland right-hander pitched with runners on base in each of the first six innings and twice had to work out of two-on, two-out jams.
"I just tried to act like number 40 in situations like that," said Griffin, who walked one and struck out three. "Just not show they have me in a situation or they have the upper hand. That's something I've learned a lot just watching Bartolo pitch."
That was in stark contrast to Griffin's previous start against the Red Sox, when he was shelled for nine runs (seven earned) over four innings on April 22.
He's come a long way since then, particularly since his last loss on June 15. Over Griffin's last five starts, he is 3-0 with a 3.00 ERA.
"(He) really made some in-game adjustments, then the command was all of a sudden there," Oakland manager Bob Melvin said. "He was even lobbying for the ninth, but I wasn't going to have him throw 120-plus pitches."
Griffin got help from the A's defense. Rookie second baseman Grant Green turned an unassisted double play in the second inning after Jarrod Saltalamacchia walked, then shortstop Jed Lowrie made an impressive recovery and throw to get Dustin Pedroia in the eighth after initially bobbling the ball.
Balfour pitched the ninth for his 25th save this season and 43rd consecutive save dating to 2012.
The A's sputtering offense managed only one extra-base hit off Boston starter Jon Lester (8-6) and one reliever, but made them hold up behind Griffin's stellar outing.
Since opening the season 6-0, Lester has gone 2-6 with a 6.27 ERA over his last 11 starts.
"(Lester) just happened to pitch on the wrong day given how effective their guy was," Red Sox manager John Farrell said. "We had a number of opportunities. Unfortunately we couldn't get anything going."
Derek Norris homered and Yoenis Cespedes added an RBI single to help the division-leading A's end a two-game losing streak and maintain their one-game lead over Texas in the West. Oakland reached 55 wins before the All-Star break for the first time since 1975.
Shane Victorino singled twice for Boston, which had won four straight.
Norris homered off Lester with two outs in the fifth.
Cespedes, mired in a 6-for-37 slump, singled in Lowrie in the sixth to make it 2-0. It was Cespedes' first RBI this month.
Lester beat the A's on April 24 when he allowed three runs over 5 2/3 innings and looked sharp early. Boston's left-hander allowed only one runner to second until Norris homered, and faced just three over the minimum through five innings.
Colon (12-3) will make his final start for Oakland in the series finale. Detroit manager Jim Leyland, who manages the AL, has said he won't use any pitcher who is used on Sunday. ... Reddick has reached base safely in 19 consecutive games. ... Newly acquired Red Sox LHP Matt Thornton arrived in Oakland before the game and was in uniform. ... Boston RHP Brandon Workman will make his first major league start on Sunday. ... The crowd of 36,067 marked the A's ninth sellout of the season. ... Umpire CB Bucknor, who was hit in the side of his facemask by a pitch from Oakland's Jarrod Parker on Friday night, did not suffer a concussion but remains hospitalized for observation. Mike Muchlinski was brought in to replace Bucknor.