The win smoothed over some lingering frustration following a rough week, one that featured a walk-off loss at Seattle and two ejections in two losses to the A's by a combined score of 22-6.
Entering the home half of the eighth with the score tied at 3, Marwin Gonzalez and Jose Altuve posted base hits to set up runners at the corners and no outs against Oakland lefty reliever Sean Doolittle.
After losing so many recent break points -- as manager Bo Porter likes to call high-leverage moments -- Dexter Fowler delivered a go-ahead RBI with a single past diving shortstop Jed Lowrie.
"Really good job of situational hitting," Porter said. "Altuve, with Marwin on the move, shooting the 4 hole and Dexter knowing the first and third situation, bringing them in. When you have speed on the basepaths, it dictates pitch selection for their guy."
The go-ahead single capped a big night for Fowler, who also drilled a solo home run in the first and has a seven-game hitting streak.
"Just simplify things at the plate and seeing good pitches," Fowler said. "I'd been swinging at some bad ones, so I settled down a little and found some that were in my zone."
Given Oakland's seven-run final inning in Friday's 12-5 triumph, the Astros kept their foot on the gas in the eighth, and it would prove necessary.
Jason Castro brought Altuve home with a base hit before ballyhooed rookie George Springer delivered another run with a fielder's-choice groundout. Marc Krauss finished the barrage with the eventual game-winning RBI on a groundout.
"The pitch that Gonzalez hit was on the outside corner., the pitch that Altuve hit was away [and] the pitch that Castro lined was in," Doolittle said. "Only one I really thought I missed my spot was to Fowler. I don't know. That's tough."
Little has come easy for this year's Astros, though, and the ninth was further proof. Brandon Moss roped a three-run shot off righty Jerome Williams with no outs, considerably slimming Houston's hard-earned lead.
Suddenly, the good vibes in Minute Maid had melted away and another A's hit had the game in jeopardy.
"Pretty interesting, huh?" Porter quipped. "I try to keep my emotions intact, though. Your thought process has to stay clear. I thought we were going to win the game the whole time.
He was prophetic in this instance. Williams settled down with a fielder's choice and fellow reliever Raul Valdes finagled out of the inning to ease the home crowd's unrest.
The late drama obscured a gutty outing by Keuchel, even though the first inning suggested it would be another long night against the Athletics. The southpaw surrendered a walk and three hits in a two-run opening frame, managing through it by inducing a double play and a fielder's choice.
"Just felt sluggish out of the gate," Keuchel said. "That's not like me, but you're not going to feel your best every time out. Feel like I was lucky to get out of it with two runs."
After that, the red-hot A's offense was mostly powerless against the lefty, as he set down 13 in a row at one point.
He wasn't overpowering, yet plenty effective by using a mix of sharp breakers and low fastballs to keep the high-flying A's frustrated with 12 groundouts. Keuchel didn't factor into the decision. He did post his fourth straight quality start, lasting 6 1/3 innings and allowing three runs while striking out six.
"He's probably pitching the best he's pitched in his career," Porter said.
Along with the A's recent dominance against Houston, Carter's power struggles have been another major story for the struggling Astros.
Carter entered Saturday with just two home runs, both against Seattle, after belting 29 last season.
He finally found some juice on his swing, mashing a two-run homer off the Community Leaders signs high up the left-field facade to give Houston a 3-2 lead in the second. All three of Carter's home runs have come in the last five games.
The teams' breezed through the next five innings, setting up a back-and-forth final third.
Williams bailed Keuchel out of a seventh-inning jam, though the A's did nab a run credited to the starter on Coco Crisp's sacrifice fly to tie it at 3.
It looked like advantage A's at that point, especially with Oakland's bullpen far fresher than Houston's.
Instead, the Astros finally held on for a win during what has been a testy series against a team that is a thorn in their side.
The win snapped a six-game home losing streak and was Houston's first victory against the Athletics in nine tries dating back to last season.