SEATTLE -- A barrage of long balls and a big day from “29th man” Tim Lopes helped the Mariners rally from a five-run deficit for a 6-5 victory over the A’s in the first game of a seven-inning doubleheader Monday at T-Mobile Park, but it was a bases-loaded walk by Kyle Lewis that proved the difference.

Lewis’ two-run homer in the fifth helped spark the comeback, and the rookie center fielder pushed across the go-ahead run with his two-out base on balls from reliever Joakim Soria in the sixth.

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Lopes, activated prior to the game as the extra player allowed for a doubleheader, drove in the tying run with his third double of the game and wound up scoring the winning run after Dylan Moore, Ty France and Lewis drew consecutive walks off Soria.

“It was a battle mentality, for sure,” Lopes said. “Our guys never feel like we’re out of it. There’s a lot of guys that believe in each other and are pulling on the same side of the rope. It was just really nice to see. It’s something I feel is ingrained in this team, from top to bottom, nobody is going to give up. We’re just trying to get a ‘W’ and we were able to do that, so it was nice.”

Lopes is the second 29th man to come through for Seattle this season. In the Mariners' only previous doubleheader in San Diego, José Marmolejos homered in both games of the twin bill, and he’s remained on the roster ever since.

“The 29th player must be our secret weapon this year,” manager Scott Servais said. “When you’re the 29th player for us, good things happen.”

The A’s spotted 22-year-old starter Jesús Luzardo a 5-0 lead before the Mariners began chipping away. Luis Torrens and Marmolejos hit solo shots, and Lewis launched his 10th home run of the season to make it 5-4 in the fifth.

Mariners starter Marco Gonzales allowed five runs on six hits and one walk in six innings, with the big blows coming on a three-run homer by Marcus Semien and a solo shot by Tony Kemp in a four-run fourth. The five runs was the most allowed by Gonzales in nine starts this season, but the late rally gave him the win as he’s now 6-2 with a 3.49 ERA. Yoshihisa Hirano pitched a scoreless seventh for his second save of the season.

Gonzales said he didn’t have his normally efficient cutter and had to battle to stay in it, but he was thrilled to see his club fight its way back after the early deficit.

“Just a joy to watch,” Gonzales said. “The boys really stepped up and had my back.”

Torrens, a 24-year-old acquired from the Padres on Aug. 30, went 2-for-3 and pushed an opposite-field shot just over the fence in right field for his first Major League home run. He’s hitting .286 (8-for-28) in eight games since coming to Seattle in a seven-player deal.

Marmolejos also has been a big midseason addition since being recalled from the alternate training site on Aug. 27 as the 29th man. The rookie left fielder is batting .367 (18-for-49) with five home runs and 15 RBIs in 15 games.

Lewis’ blast was a welcome sign for the Mariners as the American League Rookie of the Year candidate had cooled off at the plate of late, hitting just .130 (6-for-46) with two homers over his previous 14 games. But the 25-year-old center fielder jumped on a first-pitch fastball from Luzardo and drove it well beyond the center-field fence.

“K-Lew has been due,” Servais said. “He was really fired up for that. It was a great team win. There’s a lot of good vibes in this clubhouse right now.”