''We just need to win a game,'' Oakland manager Bob Melvin said. ''If you start thinking about three games ahead, you lose your focus on Tuesday's game.''
Triple Crown winner Miguel Cabrera doubled twice for the Tigers, hit a fly ball that resulted in a two-run error and later singled in the ninth.
The Tigers overcame three A's leads and seesawed to victory. It was 1-all before a wild final three innings that included a big Oakland misplay, two game-tying wild pitches and several momentum changes.
It was the sixth straight postseason loss for the A's, all to Detroit. The Tigers swept Oakland in the 2006 AL championship series, winning the series on Magglio Ordonez's homer in Game 4 - which was Detroit's last sudden-death postseason win before Sunday.
Omar Infante and Cabrera hit back-to-back singles off Grant Balfour with one out in the ninth. With men on first and third, Prince Fielder was intentionally walked, bringing up Kelly, who had stayed in the game as the designated hitter after pinch-running the previous inning.
Kelly's fly to right was plenty deep enough to score Infante without a play at the plate.
It was tied at 4 after both teams made their share of mistakes in the seventh and eighth. Cliff Pennington gave the A's the lead with an RBI single in the seventh, but center fielder Coco Crisp dropped Cabrera's two-out flyball in the bottom half, allowing two runs to score.
Oakland tied it in the eighth on a wild pitch by Joaquin Benoit, and Josh Reddick followed with a solo homer to give the A's a 4-3 lead. Then it was Ryan Cook's turn to throw a tying wild pitch, allowing Kelly to score as a pinch runner.
Pennington nearly came through again for Oakland in the ninth, but his deep drive down the left-field line was just foul. With runners on first and third and two out, Al Alburquerque got Yoenis Cespedes on grounder to the mound - and it looked like the right-hander planted a little kiss on the ball before throwing to first after he fielded the comebacker.
On a drizzly day at Comerica Park, both teams were sloppy with the game on the line.
With runners on first and second and two out in the seventh, Cabrera lifted a fly to center. Crisp, charging hard, tried to make a basket catch but bobbled the ball. He nearly recovered to make a falling grab, but the ball popped out of his glove and the Tigers took a 3-2 lead.
Cespedes led off the eighth with a single and stole second and third. With one out and the infield in, Benoit threw a wild pitch to allow the tying run. The worst was still to come for the Detroit reliever, who allowed Reddick's homer to right that put Oakland ahead 4-3.
Reddick had struck out in all six at-bats in the series before that.
Oakland again gave up the lead immediately. The A's have taken the lead four times in this series, but on each occasion they failed to hold it through the bottom half of the inning.
Doug Fister allowed two runs and six hits in seven innings for Detroit, striking out eight. Rookie Tommy Milone was impressive for the A's, allowing a run and five hits in six innings. He struck out six.
Fister gave the A's trouble early with his slow, sweeping breaking ball, but Oakland hit four singles in the third to score a run. Crisp's slow roller to third turned into an infield hit when Cabrera threw wide to first. Drew struck out looking - and had words for plate umpire Mark Wegner - but Cespedes followed with a run-scoring single.
Oakland nearly scored again on a single to right by Moss, but rookie Avisail Garcia threw Crisp out at home.
The A's showed frustration with the plate umpire during Game 1, and that spilled over to Sunday. Reddick struck out looking for the third out of the third and threw his bat away immediately. Wegner took off his mask and stared at the Oakland outfielder as he headed back toward the dugout, but the situation didn't escalate.
Cabrera hit a one-out double in the bottom of the third - to the same spot in left-center as his double in the first. He went to third on a single by Fielder and scored on a dribbler by Delmon Young that was too slow to be a double play.
Milone retired 10 in a row, starting with Young's RBI groundout.