HOUSTON -- Robinson Cano struck one last devastating blow in a season full of them at Minute Maid Park and, in the process, snuffed the life out of the Houston Astros' dwindling postseason aspirations.

Cano belted his 36th homer in the first inning and the Seattle Mariners kept afloat their own playoff hopes with a 12-4 victory over Houston on Wednesday.

The Mariners (84-74) pounced on right-hander Doug Fister in their first at-bat and never looked back, building a 7-0 lead in the third inning before holding off an Astros' rally in the sixth to claim the rubber match of this three-game series.

"Really, really happy for our guys," Seattle manager Scott Servais said. "Last night (an 8-4 setback) was one that was really tough to swallow; we kind of let it slip away. We talked about it after the game and the guys left here in a pretty good state of mind based on what happened and they showed up today ready to play."

The Astros (83-76) dropped five of seven games on their final homestand, essentially bowing out of the race for an American League wild card. They'd won 21 of 28 games against the Los Angeles Angels and Mariners before dropping series to both to remain behind Seattle and the Detroit Tigers in the chase for the second AL wild-card slot, occupied by the Baltimore Orioles entering play on Wednesday.

Cano finished 1-for-5 with three RBIs and two runs scored. In 10 games at Minute Maid Park this season, Cano hit .476 with six doubles, seven home runs and 14 RBIs.

"I love it with the way I swing here," Cano said of the ballpark. "It's like playing anywhere else. It's just a stadium that you hit better in than the other ones."

The Mariners chased Fister with one out in the second inning and extended their lead to 6-0 when left fielder Nori Aoki greeted reliever Kevin Chapman with an RBI single before Mariners right fielder Seth Smith followed with a two-run base hit.

Fister (12-13) was charged with five runs on five hits and one walk, capping a dismal final month of the season with an 0-4 record and 11.74 ERA over six starts.

"It's pretty frustrating," said Fister, a pending free agent. "I let the team down. The last couple of starts haven't gone what I would call my way at all. But it's not for lack of effort, lack of work. It's just something that I'm going to have to go into the offseason working on some things and come back ready to go."

Seattle tacked on two runs in the seventh inning before Kyle Seager belted his 30th home run, a three-run shot off Astros right-hander Pat Neshek, in the eighth to join Cano and Nelson Cruz as Mariners with 30-plus homers this season. Cruz has hit 41.

Left-hander James Paxton (6-7) allowed three runs on six hits and one walk with eight strikeouts over five innings. He surrendered a solo home run to Astros right fielder George Springer, his 29th, in the third and left with a 7-3 lead.

But Seattle reliever Nick Vincent allowed three consecutive hits to open the sixth, including Evan Gattis' 32nd home run on the first pitch of the frame. That's when right-hander Evan Scribner entered and, facing the tying run with no outs, struck out Teoscar Hernandez and Tony Kemp before inducing a Springer groundout.

"Scribner was awesome," Paxton said. "He really saved the game for us there."

Said Astros manager A.J. Hinch: "Scribner did a really good job of getting his outs and just slowing down the momentum and the flow that was going on. Obviously would have loved to have had a bigger number in the sixth, especially after the fifth."

NOTES: Astros 3B Alex Bregman returned to the starting lineup for the first time since Sept. 14 following his game-tying pinch hit in the sixth inning on Tuesday night. Bregman missed 11 games with right hamstring discomfort. ... Mariners SS Ketel Marte was in the starting lineup on Wednesday, one day after his critical throwing error opened the door for the Astros' six-run sixth inning. For Marte, it was his 20th error, the second-most among American League shortstops (Athletics SS Marcus Semien, 21). Rangers SS Elvis Andrus is the only AL shortstop with an inferior ultimate zone rating to Marte (-10.2). ... Astros 2B Jose Altuve and SS Carlos Correa both reached 96 RBIs on Tuesday night and became the first set of AL middle infielders to record 95-plus RBIs in a single season since 2B Bobby Doerr (120 RBIs) and SS Verne Stephens (144 RBIs) did so for the 1950 Red Sox.