HOUSTON -- Chris Carter continued his power surge Tuesday night, extending a run of prolific slugging that began in July. The recent run of late-game heroics by the Houston Astros designated hitter only enhances Carter's resoundingly memorable second half of the season.

Carter delivered an eighth-inning, multi-run home run for a second consecutive game, this blast supplying the Astros a 4-2, come-from-behind victory over the Oakland Athletics at Minute Maid Park.

Erasing the Athletics' 2-1 lead, Carter crushed a 439-foot, three-run shot, his 32nd home run of the season, off right-hander Luke Gregerson. Carter blasted a two-run homer in the eighth inning Monday night, but that dinger merely cut the deficit to one run in an eventual 8-2 defeat.

It was the third time in eight games that Carter belted a significant home run in the latter stages, a stretch that began Aug. 19 with a three-run, ninth-inning homer at Yankee Stadium.

"It's nice to come in clutch late in the game when we're down a couple of runs or whatever," Carter said. "It was just pure excitement right there. I knew it was a home run, a no-doubter. I was excited right there in that situation."

Carter's homer took a potential win away from A's right-hander Jason Hammel.

After enduring a nightmarish four-start stretch following his July arrival from the Chicago Cubs, Hammel produced a third promising outing this month. He was lifted following seven strong innings and just 93 pitches, having allowed one run on three hits and one walk with six strikeouts.

"That's about as well as he's pitched, certainly in the later innings," Athletics manager Bob Melvin said. "And it's huge for his confidence because certainly he's going to have some big starts for us down the stretch."

The Astros mounted their comeback when left fielder Robbie Grossman reached on an error by Oakland first baseman Stephen Vogt before Gregerson (3-3) hit second baseman Jose Altuve with a pitch. Carter then deposited a 1-1 fastball onto the train tracks in left.

"I was trying to go sinker, down and away," Gregerson said. "It started away, but it just ran all the way across the plate, down and in. Not necessarily a bad location for a lot of guys, but not for him."

Right-hander Josh Fields (4-6) worked a perfect eighth inning for the win as the Astros (56-77) snapped a three-game losing streak.

Astros right-hander Chad Qualls set the Athletics down in order in the ninth inning for his 15th save.

Houston left-hander Dallas Keuchel logged seven innings, allowing two runs (one earned) on five hits and three walks with three strikeouts.

The Athletics (77-54) pestered Keuchel for a run in the first inning, following a leadoff walk by center fielder Coco Crisp with four consecutive balls in play -- the last left fielder Jonny Gomes' RBI single to center.

Gomes factored into the Athletics' second run, in the fourth, slapping a one-out single to right-center and scoring from first when first baseman Nate Freiman added a double to left field that handcuffed Grossman.

Gomes added a sensational diving catch to close the third inning, a grab that not only robbed Carter of a hit but also enabled Hammel to strand two baserunners with the Athletics clinging to a 1-0 lead.

Center fielder Dexter Fowler got the Astros on the board with a leadoff home run in the fourth. Carter eventually finished the job.

"You've just got to tip your cap to Hammel," Keuchel said. "He threw the heck out of the ball, and thankfully Carter continued his power surge or we'd be kind of moping in here. So it was nice of him to do that."

NOTES: Eight Astros prospects will play for the Salt River Rafters in the Arizona Fall League: RHP Mark Appel, OF Andrew Aplin, C Tyler Heineman, LHP Mitchell Lambson, RHP Tyson Perez, 3B Rio Ruiz, INF Joe Sclafani and RHP Vincent Velasquez. ... Athletics SS Jed Lowrie began playing catch Tuesday and is inching toward a possible rehab assignment. Lowrie went on the 15-day disabled list retroactive to Aug. 14 with a fractured right finger. ... Astros manager Bo Porter acknowledged the likelihood of Sept. 1, when major league rosters can expand to 40 players, serving as the date when the club will reinstate OF Alex Presley (right oblique strain), OF George Springer (left quad strain) and LHP Darin Downs (right oblique strain) from the disabled list. Presley, Springer and Downs missed their 42nd, 35th and 11th games, respectively, Tuesday night.