Just like that, the Astros have a winning streak and their first series win in nearly two months.
"I was ready for the fastball and he threw it," Corporan said. "As soon as I hit it I thought it's either a homer or a double and we're going to score."
Corporan's hit came after Oakland nearly won the game in the bottom of the 10th when Houston left fielder Robbie Grossman made a leaping grab of Chris Young's deep fly at the fence.
It's the first time the Astros have had back-to-back wins since June 15-16 when they took three of four from the Chicago White Sox. That's also the last time Houston won a series.
"That was a big hit by Corporan," Astros manager Bo Porter said. "He's actually got big hits all year. You look at the year [catcher Jason] Castro's having, a lot of that credit goes to Corporan being a great backup and giving him opportunities to take days off."
Jose Altuve singled with one out Doolittle (3-4) and was headed for third on Corporan's double to left-center when Young bobbled the ball. Altuve alertly rounded third and scored the tiebreaking run while Corporan was caught in a rundown between second and third.
Corporan had entered the game as a defensive replacement in the bottom of the ninth.
"We've been playing pretty good," Corporan said. "Things are going our way now. It's our turn."
Yoenis Cespedes singled and scored Oakland's run. The A's have dropped nine of 13 and fell two games behind first-place Texas in the West.
"It just seemed like it was frustrating from the beginning and got more frustrating as the game went on," said A's manager Bob Melvin, who was ejected in the eighth inning after arguing a close play at third base.
"You have to try and put that away and keep your wits about you and not get frustrated."
Houston won despite Oakland getting the tying run on base in the bottom of the 11th.
Carter, the former A's first baseman, homered off A's starter Jarrod Parker leading off the seventh. It's Carter's third in his last five games.
Brandon Moss' RBI double in the seventh off Houston reliever Phil Humber tied it.
Both starting pitchers were stellar but left with no decision.
Houston's Jarred Cosart, the first pitcher in franchise history to begin his career with five consecutive starts of five-plus innings while allowing two or fewer runs, kept the A's silent early. He allowed only one runner past first base through six innings and didn't give up a fly ball out until Josh Donaldson's sinking liner to center leading off the fifth.
The Astros also backed him with solid defense. Houston turned a double play to end the third, and center fielder Brandon Barnes made a running catch near the wall to rob Seth Smith of extra bases in the sixth.
Parker pitched a career-best 8 1/3 innings for Oakland and had six strikeouts. The right-hander faced just two over the minimum through the fifth and made his only mistake came in the seventh when he gave up Carter's team-leading 22nd home run of the season.
Melvin was ejected in the eighth after arguing a call by third base umpire Doug Eddings.
Sogard doubled leading off the inning but was thrown out on a close play trying to advance on Nate Freiman's deep fly to center. Melvin scampered out of the dugout to dispute the call before getting tossed.
- Castro's single in the ninth extended his hitting streak to a career-best 12 games.
- Carter's home run was his first against his former club. He was traded to Houston in the offseason as part of Oakland's deal to acquire Lowrie.
- A's C John Jaso still has not been cleared to resume baseball activities but the team is hopeful he can return this season. Jaso met with a concussion specialist in Pittsburgh earlier this week.
- CF Coco Crisp was held out of the lineup after getting a cortisone injection in his wrist on Tuesday.
- The Astros called up INF Marwin Gonzalez from Triple-A Oklahoma City and optioned RHP Jorge DeLeon down.
- Houston traded minor league LHP Travis Blackley to Texas in exchange for a player to be named later and cash considerations.