DETROIT -- After a slow start in the American League, Miguel Cabrera has found his power stroke.
Gary Sheffield and Edgar Renteria also homered for Detroit, which won for the second time in nine games.
Cabrera broke open a one-run game with a three-run shot in the seventh inning, giving the Tigers a 6-2 lead.
"He's a force," Tigers manager Jim Leyland said. "We talked about how good he would be and he's gotten acclimated (to the AL)."
After A's reliever Alan Embree walked Magglio Ordonez intentionally -- after running the count to 3-0 -- Cabrera drove Embree's first pitch into the left-field stands for his 23rd home run.
"The key was Cabrera's three-run shot," Oakland manager Bob Geren said. "That was the one that was tough to overcome."
Cabrera is hitting .348 in the 22 games since the All-Star Break with seven home runs and 32 RBI. He has 89 RBI, third in the A.L., and is hitting .298.
"I know what they're trying to do to me now," Cabrera said of the AL's pitchers. Cabrera came to the Tigers in a trade with Florida in the offseason.
Frank Thomas connected for Oakland, which has lost 11 of 12.
Armando Galarraga (10-4) allowed two runs and eight hits in 5 2/3 innings for the win.
But Detroit lefty reliever Bobby Seay got the game's biggest out. Leading 3-2 in the sixth, Galarraga loaded the bases with two outs. Seay replaced him and got Daric Barton on a flyout to end the inning.
"Just come in and try and get ahead and throw strikes," said Seay, who pitched 1 2/3 scoreless innings and struck out two. "Not a lot of room for error. Just be ready to go with that first pitch."
The Tigers added four in the eighth on Brandon Inge's RBI single, Curtis Granderson's run-scoring double, Matt Joyce's a run-scoring single and Ordonez's RBI single.
Thomas gave Oakland a 1-0 lead in the first with his eighth home run of the season and 521st of his career. That tied him for 17th all time with Willie McCovey and Ted Williams.
Sheffield tied it 1-all for Detroit in the second with his 10th homer of the season. It was Sheffield's 490th career home run.
Renteria's home run leading off the third gave the Tigers a 2-1 lead. It was his sixth of the season.
The Athletics tied it in the fourth on Jack Cust's RBI single. But Cabrera homered off Dan Meyer (0-1) in the bottom half to put Detroit up 3-2.
Meyer gave up three runs and six hits in five innings.
"If you don't execute against a team like this, they will hurt you," Meyer said. "And that's what they did."