Gonzalez allowed six hits and five runs in four innings, and the Astros' bullpen allowed the game to get out of hand by allowing seven runs in five innings.
"Unfortunately for the bullpen, it was a rough outing for most of them out there," Astros interim manager Tony DeFrancesco said. "We had a couple of good games and a couple of bad games. If we can be consistent coming out of the 'pen and shut them down, that could keep us in the game. That's a good team with a solid lineup and they had a couple of big home runs."
Jimmy Rollins led off the game with a homer for the Phillies -- extended his club record to 42 leadoff homers -- and Domonic Brown provided the kill shot with a two-run homer in the seventh inning that put the Phillies ahead, 9-4.
The Astros got homers from Matt Downs and Justin Maxwell and lost despite scoring six runs for the second game in a row against the Phillies.
"If you get four runs off Cole Hamels, it's a big night offensively," Downs said. "It's always tough to put runs up against a guy like that or Cliff Lee and Doc Halladay. They swung the bats extremely well tonight and you take your hat off to them."
Hamels snapped a three-game losing streak against the Astros and has now thrown eight consecutive quality starts since Aug. 2.
"Just being able to come out and put up the runs early is huge, just because you want to just get the momentum back," he said. "Especially after last night, you want to get things rolling again and get the positive mojo going so we can get back into how we know we've been playing baseball for the last week."
After Rollins led off the game with a homer, Gonzalez allowed the next three batters to reach on a walk, a single and double, and all three scored. It was 4-0, Phillies.
"In the first inning I was struggling with the command of the fastball," Gonzalez said. "I couldn't hit the corners. They're good hitters and they got me."
The Astros, who left the bases loaded in the second, took advantage of an error in the first to score an unearned run, and Downs hit a two-run homer in the fourth to pull Houston to within two runs, 5-3.
"He kind of left a cutter back over the plate a little bit," Downs said. "He pounded one in my first at-bat, and my second at-bat he left one out over the plate, enough for me to get the barrel on it. He works that cutter to both sides of the plate, works that changeup, works his fastball. He mixes all three pitches well."
Some bad luck doomed the Astros in the fifth. With the bases loaded and two outs, John Mayberry hit a comebacker to the mound that caromed off the leg of reliever Fernando Rodriguez and rolled toward right field. Second baseman Jose Altuve scurried to field the ball and threw late to home as the second runner crossed the plate, giving the Phillies a 7-3 lead.
"It seems every time he comes in, it's a ball like that -- off his glove, off his foot," DeFrancesco said of Rodriguez. "There was a deflection and two runs scored. That kind of knocked us out of the game there. That was a big out we were trying to get with two outs."
Maxwell clubbed his 15th homer of the season with two outs in the fifth inning for Houston, clanging it off the left-field foul pole, but Brown hit a two-run homer to right field in the seventh off Jose Valdez to stretch Philadelphia's lead to 9-4.
The Phillies tacked on three more runs in the eighth off Enerio Del Rosario, including a two-run single by Ryan Howard. Despite using 25 relief pitchers in the last five games, DeFrancesco says his young bullpen isn't weary.
"I don't think it's fatigue," DeFrancesco said. "They're trying to establish themselves every day to compete and grind it out. There's so much pressure. Sometimes you see who's hitting on the other team and you see these big names you grew up watching, and all of a sudden you're facing them. All this stuff we have to overcome. We're giving every guy an opportunity to prove they belong in this uniform at the end of the season."