HOUSTON -- When a national publication this week highlighted the struggles Houston Astros right-hander Brad Peacock endures while working a third time through a batting order, it apparently served as a bit of motivation -- not necessarily for Peacock, but for manager A.J. Hinch.

Peacock staked his claim to a slot in the postseason rotation, working six strong innings as the Astros held off the Chicago White Sox 4-3 on Wednesday night at Minute Maid Park.

Peacock (12-2) allowed only one hit, a two-run homer by Yoan Moncada in the fourth inning, while recording six strikeouts and two walks. He retired the side in order in four of his six innings while producing his sixth consecutive start with two or fewer earned runs.

"I'm just not thinking about it at all," Peacock said of his postseason role. "Whatever they decide to do, like I've said before, I'll be happy. Whether it's bullpen or starting, just to get the chance to play in the playoffs is going to be cool."

The Astros (93-58) climbed a season-high 35 games over .500 by cobbling together just enough support to buoy Peacock.

Evan Gattis delivered a seeing-eye, RBI single in the second that scored Carlos Correa. Gattis scored in the fourth after working a two-out walk and coming home along with Marwin Gonzalez when Yuli Gurriel hit a double to right-center field.

Right-hander James Shields (4-7) surrendered three runs on six hits and four walks over 5 2/3 innings to take the loss for the White Sox (60-91). He struck out five.

"I thought Shields was grinding," White Sox manager Rick Renteria said. "He kept us in the ballgame. Got through almost six. I know he felt like he didn't have his best stuff today and he was really working very hard to keep us in the ballgame. And I thought he did. I thought we gave him an opportunity to get through those six."

Moncada's home run was his seventh of the season and third on the current road trip.

"Just all about making adjustments," Moncada said. "Make adjustments and try to identify how the pitcher is trying to pitch you. Trying to be aggressive in the strike zone and swing at good pitches. Mostly it's about making adjustments."

Houston's Josh Reddick tripled and scored in the seventh inning for a 4-2 lead. He came home when Jose Altuve scorched a grounder that ricocheted off Chicago shortstop Tim Anderson and into center field.

Right-hander Joe Musgrove earned his second save, working the final 1 1/3 innings for Houston, which won its sixth consecutive game to maintain its pursuit of the best record in the American League and home-field advantage in the postseason.

Peacock retired the first nine batters, on just 41 pitches, before Moncada struck. His line-drive home run to right field marked his eighth hit in five games against the Astros this season and followed a leadoff walk by Yolmer Sanchez.

That was the lone hiccup for Peacock, who stranded Anderson at third base to close the fifth inning and returned for the sixth to retire the top of the Chicago lineup in order. Peacock had allowed a 1.050 OPS when facing hitters for a third time. His work in the sixth was noteworthy.

"The third time through the order for him is an open topic," Hinch said of Peacock. "When he can block that out and go and pitch and finish his outing and walk off the mound, obviously (it) makes him feel like he accomplished something. These guys like to finish their outings, and he did in great form."

NOTES: Astros RHP Mike Fiers was activated from his five-game suspension and will work out of the bullpen in long relief. Of the 29 appearances Fiers has made this season, only one has come in relief -- a one-inning stint Sept. 8 at Oakland. ... White Sox RF Avisail Garcia departed in the middle of the third inning with stomach discomfort. Garcia made one plate appearance, striking out in the second inning, before being replaced by Alen Hanson. ... With his two-run, two-out double in the fourth inning, Astros 1B Yuli Gurriel set a franchise rookie record with his 57th extra-base hit (39 doubles, 17 home runs, one triple). Hunter Pence set the previous mark of 56 in 2007.