SEATTLE (AP) — Matt Olson hit a grand slam that capped a six-run fifth inning, Khris Davis added his major league-leading 47th home run and the Oakland Athletics beat the Seattle Mariners 9-3 on Wednesday night to close on the New York Yankees for home-field advantage in next week’s AL wild-card game.

With the score 3-3, Nick Martini hit an RBI single that chased Felix Hernandez (8-14), who made his first appearance since gaining American citizenship this week. Marcus Semien added a run-scoring single against Chasen Bradford before Olson’s drive to right-center.

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Oakland (96-63) improved to a big league-best 41-21 since the All-Star break and trails the Yankees (97-61) by 1 1/2 games. New York holds the tiebreaker to host the Oct. 3 game; the wild-card winner advances to the Division Series against AL East champion Boston.

Chad Pinder also homered for the A’s, who reached 96 wins for the first time since 2013.

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Ryan Buchter (6-0) pitched a hitless inning in relief of Edwin Jackson who gave up three runs and five hits in 4 1/3 innings.

Hernandez, a 32-year-old Venezuelan who won the 2010 AL Cy Young Award, was sworn in as a U.S. citizen on Monday. He gave up five runs — four earned — three hits and two walks, and finished with a 5.55 ERA, more than a run above his previous career-high last year. His ERA has more than doubled since he led the AL in 2014 at 2.14.

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