Sanchez, who had a three-run, inside-the-park homer in Monday's 9-3 win, went 3-for-5 with two more RBIs. The Pirates have scored 17 runs in two games against the Astros after scoring only nine in four games in Colorado, all losses.
Pittsburgh rallied for seven runs in the ninth inning on Monday and manager John Russell thinks the outburst relaxed his team. It showed Tuesday night, as the Pirates scored in four of the first five innings and finished with 11 hits.
"Hitting is contagious," said Doumit. "We've got some thunder in this lineup. Hitting has never been the question with us this year. That Colorado series was a tough one for us, but we've kind of found our swings again and we want to keep going."
The Pirates' bats were complemented by Maholm (7-6), who allowed a run on five hits, all singles, and struck out five. The 25-year-old left-hander won for the fifth time in six decisions and improved to 2-5 on the road this season.
Maholm badly wanted to atone for his 5-3 loss to the Rockies last Thursday, a game that the Pirates led 3-0.
"I've been pitching solid for a good while," he said. "I let myself down and the team down. We had a 3-0 lead there and I kind of let them back in the game. It was frustrating, but it's part of the game and you've got to understand that.
"I prepared how I always do, went out and saw what I had and just worked with it."
Maholm was perfect through 3 1/3 innings until Michael Bourn singled in the fourth.
Doumit, Pittsburgh's catcher, said Maholm looked sharp in pre-game warmups.
"Every time he takes the hill, we feel extremely confident," Doumit said. "I saw from the bullpen that it was going to be one of those days."
Pence said Maholm kept the Astros off-balance all night.
"He threw strikes and he found a way to get a win," Pence said. "I felt like the ball wasn't bouncing our way."
Sanchez went 3-for-5 with two more RBIs. He hit a solo shot in the first inning off Houston starter Jack Cassel (1-1), though Sanchez wasn't sure if it was a home run at first.
The ball hit high off the wall in left-center and Sanchez stopped at second. But after Russell protested, the umpires conferred and ruled the ball hit above the yellow line running along the fans' balcony for a home run.
"I couldn't tell," Sanchez said. "I had my head down running. I didn't know what to expect."
With one out in the third, McLouth drove an 0-2 pitch from Cassel into the restaurant area in center to make it 3-0. McLouth has 18 of his 20 homers this season against right-handed pitchers.
Jack Wilson led off the fifth with a double to left-center and scored on Sanchez's single to left. Sanchez later scored on Jason Bay's single to make it 5-0 and Houston manager Cecil Cooper brought in Chad Paronto to relieve.
"Jack has to be perfect. When he isn't, he gets in trouble," Cooper said. "When you don't throw with very much velocity, you've got to hit your spots."
The Pirates added three in the seventh when Wilson walked and Sanchez doubled before Doumit drove the first pitch he saw onto the railroad tracks in left field, his 12th homer of the season and fourth hitting right-handed.
The Pirates are 17-7 against the Astros since the start of last season.
Sanchez has four homers in his last 12 games at Minute Maid Park. ... Bay has 11 RBIs in his last eight games. ... Cassel was 6-1 with a 1.92 ERA in 10 minor-league starts this season. He had an 0.64 ERA in his last three starts at Round Rock before he was called up late Monday. ... Before the game, the Astros acquired LHP Randy Wolf from San Diego in exchange for minor leaguer Chad Reineke. The Astros said Wolf will start Sunday in Milwaukee.