OAKLAND, Calif. -- Right-hander Jesse Chavez bounced back from his worst start of the season and pitched seven solid innings Saturday, leading the last-place Oakland A's to a 2-1 victory against the first-place Houston Astros at the O.co Coliseum.

Chavez (6-11) allowed one run on six hits, striking out four and walking four as the A's beat the American League West leader for the second straight time. In his previous start, Chavez gave up six runs in 3 2/3 innings in a 9-2 loss to Baltimore. He had gone 1-5 with a 6.23 ERA and .322 opponent batting average in his past seven starts.

"It's a good confidence-builder after what happened last time," Chavez said.

A's starting pitchers have now allowed one or fewer runs in seven of the past nine games.

Designated hitter Danny Valencia hit a two-run double in the first inning, giving Chavez all the run support he needed. Valencia, claimed off waivers from Toronto on Monday, went 2-for-4 in his second straight start, hitting fourth in the order again. He went 1-for-3 with a home run Friday night in a 3-1 win against the Astros (61-51).

"It feels good," Valencia said. "It feels better when you come through to help the team win. It was nice to be out there today, it was nice that we won this game. Jesse did a great job."

The Astros made it interesting in the top of the ninth. Pinch hitter Jed Lowrie worked a leadoff walk against left-hander Drew Pomeranz and gave way to pinch runner Jake Marisnick.

Right-hander Edward Mujica retired first baseman Chris Carter on a line drive to left but balked Marisnick to second. Marisnick tagged up and raced to third on catcher Hank Conger's flyout to center.

But Mujica got second baseman Jose Altuve on a ground ball to third, ending the game to earn his first save of the season.

"I just try to go aggressive every single night with my pitches," Mujica said. "I put the ball where I wanted and I got those three outs."

Astros right-hander Collin McHugh (13-6) allowed two runs on five hits over six innings and threw a season-high 121 pitches as his four-game winning streak ended. McHugh left the game with Houston trailing, 2-1. He struck out eight and walked three.

"I put us behind the eight-ball from the beginning," McHugh said. "It took a little while to find a feel for my pitches. I went the whole day without having very good command or very good stuff. We were in it the whole time.

"Their starter threw the ball well and their bullpen came in and did the job. I have to be better early. I have to be a little sharper earlier and give us a chance to get on top."

Left fielder Preston Tucker hit a solo home run, his 11th shot of the season for the Astros. Altuve went 2-for-5 and extended his hitting streak at the Coliseum to 19 games, the longest active streak in the major leagues.

The A's (50-62) took a 2-0 lead in the first inning. McHugh issued walks to center fielder Billy Burns and left fielder Coco Crisp to start the frame. Then, with one out, Valencia lined an opposite-field double to the right-center alley, driving in Burns and Crisp. Crisp left the game after the second inning because of an illness.

"They play me on a pull shift, and typically I like to drive the ball mostly to left-center," Valencia said. "But he's a guy that throws cutters and off-speed out over the plate away, so my approach really was to stay that way.

"He gave me a pretty good pitch to hit in a hitter's count and I was able to hit it hard enough to cut the gap and score a couple runs."

The Astros answered with a run in the fourth inning when Tucker launched Chavez's 1-1 curve over the right-field fence, but that was their only run of the day.

"There's no frustration at all," Altuve said. "It's just two games, it's not a reason to panic."

Chavez struggled in the fourth and fifth innings, giving up three hits, including a home run and double, but he survived to pitch seven.

"I think the big key was not rushing in those situations, not let the situation get the best of me," Chavez said. "When things are going good, you don't think about it, but then you get in a little trouble you try to rush and get out of it as quick as you can instead of taking it just pitch by pitch. I think that's what helped me out in those middle innings."

NOTES: Houston LHP Oliver Perez, who was acquired late Friday night from Arizona in a trade for minor-league LHP Junior Garcia, was to join the Astros on Saturday night and be activated Sunday. He will give Houston a second left-handed reliever, joining Tony Sipp. "Another left-handed pitcher can be very advantageous for us," Astros manager A.J. Hinch said. "Then -- when you throw on top of that he's good, he's got experience, he's pitched in a variety of roles -- it'll be a good addition for us." ... The Astros optioned RHP Asher Wojciechowski to Triple-A Fresno after the game. ... A's LHP Sean Doolittle (strained left shoulder) said he felt "a little rusty" Friday in his first rehab appearance for Class A Stockton, despite throwing a scoreless inning. "I was just a little out of sync," said Doolittle, who added that he expects to pitch another inning for Stockton on Sunday.