L.J. Hoes hit a home run with one out in the top of the 12th, and the Astros beat the A's 3-2 on Tuesday night for their first victory in four tries at the Coliseum this year.
The Astros also earned their first three-game winning streak against the A's in franchise history.
Oakland has been impressed with the strides made by its AL West opponent.
"They're a big-league club. They're going to win, they're going to compete," catcher John Jaso said. "I was surprised [it went out]. I thought it would hit off the wall."
Hoes connected off Fernando Abad (2-4). The baseball-leading A's (61-38) missed several chances to move a season-high 25 games over .500.
Earlier in the day, Hoes' mother, Gale, asked her son to hit a home run for her as she celebrated her birthday.
"It's a really good feeling considering it was my mom's birthday, and that was the last thing she told me to do, to get a homer for her," Hoes said. "To be able to do that for her was a special thing."
Jose Altuve hit a one-out single in the 10th and tried to steal second. Initially called safe, A's manager Bob Melvin challenged that second baseman Nick Punto tagged him in time. The call was overturned in 1 minute, 3 seconds.
That ended a franchise-record 28 consecutive steals by Altuve without being caught.
Chad Qualls finished for his 11th save in 13 opportunities.
Jed Lowrie tied the game on a sixth-inning sacrifice fly.
Scott Kazmir, who had won his previous two starts and was going for victory No. 12 on the year, struck out six in seven innings. He allowed seven hits and two runs in a duel of lefty starters.
Altuve led off the game with a single up the middle, but center fielder Craig Gentry threw him out at second trying to stretch it for extra bases.
Brett Oberholtzer, making his second start since being recalled from Triple-A Oklahoma City on July 12, remained winless in four starts against the A's dating to last season. He didn't strike out a batter for the first time in 13 starts this year.
"Obes did a great job, seven strong innings against a really strong Oakland lineup, and our bullpen obviously did a tremendous job just keeping it right there," Astros manager Bo Porter said. "All those guys passed the baton from one guy to the next."
Astros first baseman Jesus Guzman returned after sitting out Sunday's series finale against the White Sox because of back spasms
When Houston last visited the Coliseum in April, Porter left the dugout in the third to yell at Lowrie moments after the No. 2 hitter flied out following two inside pitches.
Lowrie said the situation dictated that he try to bunt, and it was too early in the game not to look to score even after the A's scored seven runs in the first and led 8-0 after two.
"I respect the game of baseball, and I will leave it at that," Porter said beforehand. "I know it's completely behind me, it's completely behind our team, and it's not even something I would want to drum back up."
Astros outfielder George Springer missed his second straight game with soreness in his right knee and quadriceps.
Gentry stole his 17th and 18th bases in the A's third. ... The game drew 22,908, a strong showing for a weeknight against the Astros. ... RF Josh Reddick returned from a second stint on the disabled list because of a right knee injury but didn't start. He entered as a pinch-hitter leading off the eighth and stayed in the game. ... A foot issue is keeping Oakland's Stephen Vogt from catching right now. ... A's All-Star 3B Josh Donaldson won the Heart and Hustle Award again. "Those are probably as good of words as you can come up with for him," Melvin said. "He's dirty all the time."