Josh Donaldson belted the tying two-run homer in the ninth inning and Brandon Moss won it with a three-run shot in the 10th to give the Oakland Athletics a dramatic 7-4 triumph over the Seattle Mariners.
The A's -- winners of their last two -- reduced their magic number to three for clinching a playoff berth.
"We focus on playing one game at a time," Donaldson said. "Every game out there is the biggest game of the year for us. We've been playing playoff baseball for the last month."
Josh Reddick walked with one out in the ninth, and Donaldson followed with a homer to center field off Tom Wilhelmsen.
In the 10th, Coco Crisp singled to lead off against Oliver Perez (1-3). Stephen Pryor entered from the bullpen with one out and he walked Yoenis Cespedes prior to Moss' blast to right field.
Oakland starter Dan Strailey lasted just 4 1/3 innings, giving up four runs -- three earned -- on three hits. He walked four and struck out three.
But Pedro Figueroa, Pat Neshek, Evan Scribner and Ryan Cook combined for 4 2/3 innings of scoreless relief for Oakland, giving the A's lineup a chance to tie the game back up in the ninth.
In taking a no decision, starter Jason Vargas pitched seven solid innings for Seattle, allowing just one run on five hits, while striking out seven and walking none.
"He easily could've had 17 or 18 wins," Mariners manager Eric Wedge said of Vargas. "I love the way how he finished it off today and how he pitched and the way he competed. He put together a complete season and really came into his own this year."
He was backed by Seattle's bats in the early going, which got him a four-run lead to work with. Michael Saunders hit a two-run homer and Kyle Seager added a solo shot for the Mariners, losers of their last two.
Seattle jumped out to an early 1-0 lead, taking advantage of a leadoff walk and two consecutive errors in the second.
After John Jaso was issued a free pass from Straily, Justin Smoak hit a grounder to Moss at first base, who tried to throw to second for the force out. But Moss sailed his throw into left field for one error -- and then Cespedes committed a second error when his throw back to the infield was errant, allowing Jaso to go all the way home.
In the fourth, Seager hit a leadoff shot, and was followed three batters later by Saunders, who jacked a two-run homer to right to make it a 4-0 game.
Oakland responded in the bottom of the frame, with Moss hitting an RBI single to right to drive in Cespedes, who had singled in the previous at-bat.
Vargas then retired 12 of the next 13 batters he faced before reliever Carter Capps came in to start the eighth.
Though Capps began by striking out Cliff Pennington, he surrendered a single to Coco Crisp and then walked Stephen Drew to put runners at first and second with one out.
Wilhelmsen came into the game to face Cespedes, who popped on a foul ball to first. Crisp then stole third and scored on Moss' double to right, making it a 4-2 game, but the inning ended when Drew was gunned down at home plate.
In the ninth, the A's got a one-out baserunner when Reddick worked a walk off Wilhelmsen, who then surrendered Donaldson's two-run, game-tying homer.
Grant Balfour (3-2) tossed a 1-2-3 10th to earn the win.
The A's are now 11-7 in the season series against the Mariners ... Saunders hit his 19th home run of the season, to go along with 20 steals. The Mariners have not had a 20-20 player since Mike Cameron in 2002 ... Entering the game, Wilhelmsen hadn't allowed a run in his last 12 1/3 innings of relief.