OAKLAND,Calif. (AP) — Stephen Piscotty and Matt Chapman homered, Matt Olson had three hits and the Oakland Athletics defeated the Seattle Mariners 7-5 on Friday night.

Oakland pulled 1 1/2 games behind first-place Houston — which lost to the Los Angeles Angels — in the AL West, and extended its lead for the second wild card over Seattle to 5 1/2 games.

The A’s have won 20 of their last 29 games and are 26-13 since the All-Star break.

The Mariners have lost four of their last five.

After squandering an early 5-0 lead, the A’s scored the go-ahead run in the bottom of the fifth and then turned to their shutdown bullpen, which combined for 4 2/3 innings of scoreless relief after Mike Fiers was rocked in his shortest outing of the season.

Yusmeiro Petit (6-3) pitched 1 1/3 innings for the win.

Blake Treinen worked a scoreless ninth for his 34th save after Fernando Rodney, Lee Trivino and Jeurys Familia each pitched one inning.

Olson singled leading off the fifth and scored the go-ahead run on Ramon Laureano’s sacrifice fly.

The A’s extended their lead to 7-5 in the sixth when Khris Davis singled in Jed Lowrie.

Fiers gave up five runs in 3 1/3 innings in his worst start since coming to Oakland in a trade with the Tigers on Aug. 6.

Piscotty’s 19th home run — a two-run shot to left off Mariners starter Mike Leake — highlighted a five-run first inning in which the A’s sent nine men to the plate.

Chapman started the inning with his 22nd home run — a solo shot to left — and Olson had an RBI double.

Leake (8-9) gave up six runs and 11 hits with two walks in 4 1/3 innings. He lost his fourth straight decision and is winless in his last 11 starts.