OAKLAND, Calif. -- The Texas Rangers were coming off a three-game series sweep of the Seattle Mariners and making a strong push in the American League wild-card race when they faced the Oakland Athletics on Friday night.

The last-place A's did what they had done against the Rangers the previous five times they met at the Oakland Coliseum, delivering yet another blow to their playoff chances.

Kendall Graveman threw seven strong innings, Matt Olson hit a two-run homer and the A's defeated the Rangers 4-1.

The Rangers (76-77) fell 3 1/2 games behind the Minnesota Twins, who defeated Detroit 7-3, for the second wild-card spot in the American League. Texas remained tied with the Los Angeles Angels.

"We haven't been able to play good baseball here in Oakland," Rangers shortstop Elvis Andrus said. "But we got to scratch that out and stay positive. Tomorrow is a big game for us. Today's a game to put aside."

The A's (70-83) won their fifth straight game overall and sixth straight against Texas at the Coliseum. They used what's become a familiar winning formula lately -- an Olson home run plus a pitching gem.

Olson hit his 24th homer of the season in the second inning of just his 57th game this season. He has six home runs in his past seven games and 13 homers in September, the most in major league history by a rookie and tied with Jason Giambi for the most in A's history.

"To say it's a surprise anymore, I'd be lying because you have a good feeling when he's up there every time," A's manager Bob Melvin said. "It's amazing. It really is. He's at a point now where he just has a good feeling every time he goes to the plate."

Shin-Soo Choo hit a solo home run in the third inning, his 21st shot of the season, and Adrian Beltre had his 22nd double, but the Rangers fell farther back in the wild-card race with only nine games left.

"At the end of the day tomorrow, we could quite possibly be back to 2 1/2 games back," Rangers manager Jeff Banister said. "You've got to continue to play this game. The game of baseball is such that there are nights (like this), and unfortunately, we had one of those nights here in late September."

Graveman (6-4) allowed one run and six hits with four strikeouts and three walks. He improved to 3-0 against the Rangers this season and is 5-0 overall at the Coliseum.

"I thought the changeup was really good tonight, so we used it," Graveman said. "I think that's been a pitch over the last six weeks that's kind of come into play."

Graveman escaped a two-out, bases-loaded jam in the sixth inning, striking out Rougned Odor to end the threat.

Rangers right-hander Nick Martinez (3-7) allowed four runs (three earned) and five hits in six innings. He struck out six and walked one.

"I felt great," Martinez said. "Just kind of one pitch that I thought was a good pitch but maybe at the wrong time. Other than that, I thought we had a great game plan going into it."

Oakland's Chris Hatcher pitched a perfect eighth inning. In the ninth, Blake Treinen allowed an infield single to Brett Nicholas and a double to Drew Robinson with two outs, but he struck out Choo for his for 10th save of the season.

The A's took a 2-0 lead in the bottom of the second inning when Khris Davis led off with a walk and Olson followed with a home run. Olson lined Martinez' 1-2 fastball into the right field seats, giving Oakland a lead they never relinquished.

"We're playing really good baseball right now," Olson said. "While we might be out of it, we're still happy we're playing and that we have something to take into next year. We want to finish up strong."

Texas cut Oakland's lead to 2-1 in the top of the third on Choo's towering home run down the left field line off Graveman.

The A's answered with a run in the bottom of the inning. Marcus Semien reached base with one out on an error by third baseman Drew Robinson, stole second and scored on Jed Lowrie's two-out single.

Oakland extended its lead to 4-1 in the fifth inning when Semien doubled to left center with one out and scored on Matt Joyce's single to center.

NOTES: A's CF Chad Pinder hit his head against the outfield wall in the fifth inning while trying to catch Rangers 3B Adrian Beltre's double but remained in the game. A's manager Bob Melvin said Pinder would be examined again Saturday. ... Rangers CF Carlos Gonzalez appeared in his third game and made his second straight start after missing nine games with a sprained right ankle. ... A's CF Boog Powell had an MRI on Friday morning that showed a bone bruise but no ligament damage in his left knee. Powell was hurt on Sept. 16 against Philadelphia at Citizens Bank Park while trying to climb the center field wall to make a catch on a home run. ... Oakland C Bruce Maxwell is going through the concussion protocol and missed Friday night's game. Maxwell left Oakland's game on Wednesday at Detroit in the bottom of the ninth inning after taking a foul tip off his mask. ... A's RHP Jharel Cotton (strained groin) threw a bullpen on Friday and will start Sunday in the series finale against Texas. Cotton was scratched from his last schedule start on Sept. 18 at Detroit after being injured while warming up.