Matt Olson homered off left-hander Tony Sipp leading off the bottom of the 10th inning Friday night, completing a comeback that delivered the Oakland Athletics a 4-3 win over the Houston Astros in the opener of a three-game series between the top two teams in the American League West in Oakland, Calif.

Nick Martini lashed a game-tying RBI double in the ninth to force extra innings for the A's (73-49), who moved within one game of the first-place Astros (74-48).

Olson belted Sipp's sixth pitch well over the fence in right field for his 23rd home run of the season and Oakland's eighth walk-off win of the year.

A's closer Blake Treinen (6-2), who worked the top of the 10th in a tie game, was credited with the win after a three-strikeout effort. Sipp (2-1) took the loss.

Down 3-2 going to the bottom of the ninth, the A's rallied off Astros closer Hector Rondon to tie the game on a one-out double to the fence by Martini that scored pinch runner Ramon Laureano, who had originally been called out on a relay from right fielder Josh Reddick to shortstop Carlos Correa to catcher Martin Maldonado.

But the A's challenged the call and got it reversed upon review.

Rondon then stranded the potential game-winning run in scoring position by getting Matt Chapman to pop out and, after intentionally walking Jed Lowrie, inducing Khris Davis to fly out.

The Astros had taken a 3-2 lead in the sixth inning on an RBI single by Reddick that scored Marwin Gonzalez, who had walked.

Alex Bregman and Maldonado had earlier home runs off A's starter Edwin Jackson, giving the Astros a 2-0 lead. The homers were Bregman's 23rd and Maldonado's first since joining the Astros and sixth overall.

The A's got even in the fifth thanks in large part to an error by Correa that loaded the bases with no outs. Jonathan Lucroy then grounded into a double play, plating the first run, before Chapman's two-out single tied the game.

Neither starting pitcher got a decision.

Astros right-hander Charlie Morton, who stood two outs away from a 13th win before Martini's ninth-inning hit, worked five innings, allowing four hits and two runs (one earned). He walked two and struck out four.

Jackson also was pulled after five innings, having given up two runs on five hits. He walked two and struck out two.

Olson and Lowrie had two hits apiece for the A's, who were opening a six-game homestand.

The loss was the Astros' first of the season in Oakland after six earlier wins. Houston retained a 9-5 lead in the season series.

The A's out-hit the Astros 8-6.

--Field Level Media