OAKLAND, Calif. -- Catcher Mike Zunino is heating up just in time for the Seattle Mariners' wild-card playoff push.

Zunino hit a two-run homer in the second and sparked a ninth-inning rally with a leadoff double, leading the Mariners to their fifth straight victory with Sunday's 3-2 win against the Oakland Athletics at the Oakland Coliseum.

The Mariners remained 3 1/2 games back in the race for the American League's second wild-card spot. They swept the A's in Oakland for a second time this season, a franchise first.

Since an 0-for-20 skid in his final seven games in August, Zunino has hit .263 with two home runs, a double and four RBIs in seven September contests.

"I tried to make some little tweaks to try to improve on what I was doing and they sort of took me in the wrong direction," Zunino said. "So it was just sort of going back to what was working the whole year. And it was nice, because when you have so many at-bats and taken that swing so many times, it was pretty easy to go back to it."

The Mariners snapped a 2-2 tie with a run in the top of the ninth inning off A's closer Ryan Madson (5-5). Zunino lined a leadoff double down the left-field line and then gave way to pinch running Ben Gamel. Zunino jumped on Madson's first pitch.

"When you get the closer in there you want to either hop on him early or try to wait him out," Zunino said. "We had a decent report on him saying the first pitch is usually the best pitch to get, so I didn't want to waste any time. I was able to get on top of it and drive it."

Gamel moved to third on Leonys Martin's single to right and scored when Ketel Marte singled sharply to center.

Mariners closer Edwin Diaz pitched a one-two-three ninth for his 15th save.

"He had good swings all day," Mariners manager Scott Servais said of Zunino. "Ketel Marte, great job today. Kept getting on base, doing his thing and then a big knock at the end. Leonys, he's a different cat. There's stuff that goes on every game with him. He didn't get the bunt down but he got the big hit to get that rally going. Nice team win."

Mariners left-hander James Paxton held the A's to two runs on five hits over six innings, despite having to stay away from his cutter because of a lingering problem with a loose nail on his left middle finger. Paxton, who struck out three and walked two, relied more on his curveball and change-up than usual.

"It's an adjustment, but there were years before this one where I didn't use the cutter, and we just had fastball, curveball change-up," said Paxton, who had a no-decision. "I was with Zunino those years too, so he knows how to call my game without the cutter."

A's rookie right-hander Raul Alcantara allowed two runs on seven hits over 5 2/3 innings and got a no-decision in his second career major-league start. He struck out four, walked one and threw 104 pitches.

"He has an electric fastball, his change-up is a plus pitch and he threw some good breaking balls too," A's catcher Stephen Vogt said of Alcantara.

In his major-league debut last Monday, Alcantara gave up five runs on five hits over three innings and hit three batters -- all in the first inning -- in a 10-7 loss to the Los Angeles Angels.

"I focused on pitching my game and not making the perfect pitch like last time," Alcantara said.

The Mariners took a 2-0 lead in the top of the second when Adam Lind walked with two outs and Zunino crushed Alcantara's 1-2 pitch into the left-field seats for his 11th home run of the season.

"It was just another at-bat where I felt like I got to two strikes pretty quick, but he showed me the slider early and I was able to lay off of it, and he threw another one that was in the zone and up," Zunino said. "I was just able to get up in the zone and barrel it."

Oakland answered with two runs in the bottom of the second. Khris Davis, Ryon Healy and Vogt opened the inning with consecutive singles to load the bases. Paxton walked Brett Eibner, forcing in a run, and Yonder Alsono hit a sacrifice fly.

The Mariners had runners on second and third with two outs in the sixth, but reliever Ryan Dull came on to retire Zunino on a pop up to end the inning.

After Paxton exited, Evan Scribner gave up a triple to Eibner with one out but pitched a scoreless seventh inning. Steve Cishek (3-6) pitched a scoreless eighth, stranding a runner at second, and Diaz closed out the game.

NOTES: The Athletics released veteran DH/1B Billy Butler before Sunday's game. Oakland signed Butler to a three-year, $30 million free-agent contract on Nov. 19, 2014, but he hit just .258 with 19 home runs and 96 RBIs in 236 games. Butler appeared in only 85 games this season and had started only one time in the previous five games. "It's uncomfortable for a guy like him to sit on the bench," A's manager Bob Melvin said. "His at-bats were drying up. It was just time to move on. He wasn't going to be in the plans for next year." Butler was involved in a clubhouse fight last month with teammate Danny Valencia, resulting in a concussion for Butler and fines for both players. ... Mariners 1B Adam Lind sprained a finger on his right hand in the bottom of the second inning while making a diving stop of a ground ball. "It's not broke," Mariners manager Scott Servais said. "He had X-rays. He could be out a couple days and we'll see where it goes from there." Lind left the game in the bottom of the fifth inning. ... Athletics RHP Sonny Gray (strained right forearm) threw off a mound Sunday for the first time since going on the disabled list Aug. 7. Gray threw 11 pitches, all fastballs. He said he's hopeful of getting into a game before the season ends. Gray will throw another bullpen session in a few days at Kansas City.