Seth Smith's three-run homer punctuated a seven-run third inning, as Oakland dumped Houston, 7-2, in the finale of a four-game series.
Brandon Moss finished with three hits and drove in two for the Athletics, who took the final three in the set and have won eight of 10 overall. Yoenis Cespedes and Daric Barton added an RBI each in the triumph.
Bartolo Colon (15-6) scattered five hits and one run, fanning seven with only one walk over six innings. The 40-year-old right-hander picked up his first positive decision since July 26 against the Angels, having gone 0-3 with two no-decisions since then.
"Good movement, good location. A lot of good things came out of Bartolo's outing for us today," A's manager Bob Melvin said.
Jose Altuve and Brandon Barnes knocked in a run apiece for the Astros, who stumbled to their 10th loss in 13 and are quickly approaching their third straight 100-loss campaign.
Pressed into service after scheduled starter Paul Clemens was scratched with a blister, Lucas Harrell (6-16) was torched for seven hits and seven runs over three full frames.
"When you pitch out of the bullpen, the one good thing about that is you come to the ballpark every day believing that you're going to pitch," Astros manager Bo Porter said. "I don't think the short notice had anything to do with his performance."
Oakland assumed control with a big third inning. Stephen Vogt and Eric Sogard singled around a Coco Crisp fly out, then Vogt moved to third on Jed Lowrie's fly to right ahead of a two-run double from Moss.
Cespedes followed with a single to score another, then after a walk to Alberto Callaspo, Barton scored Cespedes with a base hit and Smith capped the rally with a three-run blast for a 7-1 game.
Houston's only answer after the burst was Barnes' RBI single in the seventh off Brett Anderson which scored L.J. Hoes.
Anderson retired five in a row from there, then walked pinch-hitter Jake Elmore and Hoes to begin the ninth. He bore down and retired the final three batters of the contest.
Houston picked up a run in the first inning as Jonathan Villar began the game with a single and came home when Altuve followed with a double.