SEATTLE -- 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.
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.
Oakland Athletics
CLOSING IN:
Mariners LHP James Paxton may start Saturday against Texas, giving him a chance to get the single strikeout he needs to reach 200 for the first time.
FRONT OFFICE:
Seattle hired Frankie Thon Jr. as head of amateur international scouting. Thon spent the previous two seasons with the Los Angeles Angels and before that was with Arizona for eight seasons. Triple-A manager Pat Listach was let go after the season and Mike Micucci is not expected to return as minor league coordinator.
TRAINER'S ROOM:
Athletics: Relievers Lou Trivino (sore neck) and Cory Gearrin (triceps) were slightly improved but did not pitch.
UP NEXT:
Athletics: RHP Mike Fiers (12-7, 3.31) starts Friday's series opener at the Los Angeles Angels.
Mariners: LHP Marco Gonzales (13-9, 4.12) pitches Thursday's series opener against Texas and RHP Ariel Jurado (4-5, 6.66).