Omar Infante got it started in the ninth with a single to right with one out. Miguel Cabrera then singled to center. Fielder was intentionally walked by closer Grant Balfour.
Don Kelly stepped up to the plate with the bases loaded and hit a sacrifice fly to right field for the game winning RBI as Infante scored.
The Tigers and the A's went back and forth in a thriller late in the game.
The Tigers, down 2-1, took the lead in the bottom of the seventh on a Coco Crisp error that plated two runs.
The Athletics went into the top of the eighth down 3-2. Yoenis Cespedes got on base with a base hit. He stole second base and then stole third base.
Cesdepes wound up scoring on a wild pitch by Juaquin Benoit with Josh Reddick up at bat. Following the wild pitch, Reddick got a hold of one and sent it over the right field fence to give the A's a 4-3 lead.
The Tigers battled back to tie the game in the bottom of the eighth and they scored on a wild pitch by Ryan Cook.
The Tigers now fly to Oakland where they will try to put the series away.
That game will be played on Tuesday, October 9 at 9 p.m. ET. Anibal Sanchez will be on the mound for Detroit. Oakland's starter is still TBD.