Zambrano (1-2) pitched well enough to win in his five previous starts, with a 2.53 ERA in 32 innings, but the Marlins suffered blown saves in three of them. Zambrano took no chances this time, throwing a complete-game three-hitter. He struck out nine and gave up just three singles. He walked only one, but did hit two batters.
The right-hander did not allow a runner past first base all night long. Four double plays turned by the Marlins' infield helped keep Astros baserunning to a minimum. Zambrano threw 110 pitches, 69 for strikes.
Marlins manager Ozzie Guillen summed it up in one word: "Strikes."
"First victory, complete game, what more could I ask for," Zambrano said. "Everything was working and I was using all my pitches."
Marlins catcher John Buck said he was happy to see the veteran earn his first win with the club.
"So many people gave up on him one reason or another," Buck said. "Since he walked in here, he's been nothing but awesome from every way you can think of. He was uplifting when things weren't going great. To see him pitch so well and benefit on the field is cool, because he's been through a lot and he's endured a lot.
"He's kind of a favorite in this clubhouse."
Buck was one of three Marlins to belt homers off Houston starter Wandy Rodriguez (3-3), accounting for all of Miami's runs. Giancarlo Stanton and Hanley Ramirez popped the other two, providing plenty of offense for Zambrano to finally break into the win column.
Stanton and Buck went deep in the fourth and fifth, respectively, and Ramirez opened the ninth inning with his sixth homer of the season in the opener of a three-game series that will conclude the Marlins' most successful road trip in franchise history.
The seven road wins, which includes three-game sweeps of San Francisco and San Diego, is their most ever in a nine-game trip, surpassing 6-3 marks accomplished seven different times.
Stanton extended his hitting streak to 10 games in a big way. The right fielder broke a scoreless tie by yanking a 1-0 offering into the Crawford Boxes just beyond the left-field fence for a 2-0 lead. Logan Morrison, who drew a one-out walk, scored ahead of him.
It was Stanton's sixth homer during the streak, and fifth on this nine-game road trip.
Buck made it 3-0 an inning later. The catcher led off the fifth by taking the first pitch from Rodriguez the opposite way, clearing the right-field fence by a handful of rows.
Ramirez piled on, belting a 2-2 pitch onto the railroad tracks above the Crawford Boxes to lead off the ninth.
That's the one that convinced Guillen to allow Zambrano to finish. Guillen said he gave brief thought to lifting Zambrano in the ninth, but his veteran pitcher would have nothing of it.
"He said he wanted one more inning," Guillen said. "We had [Steve] Cishek ready, but there was really no doubt in our minds that he was going to go back out there. He had 90-something pitches. And then Hanley's home run made [the decision] easy for him to go out there and finish."
Zambrano is now 10-4 in 17 lifetime starts (19 appearances) at Minute Maid Park.
He made quick work of the Astros, finishing the job in two hours and nine minutes.
"I like to pitch fast," Zambrano said. "No walking around the mound and don't let the hitter think. When you're in the zone, commanding your pitchers, you can throw games in two hours."
That makes it fun for a catcher, as well.
"His ball moves all over the place and he was able to control his sinker and his cutter," Buck said. "That opens a lot of options for me as it goes into the at-bat. And then [he also threw] a split-finger.
"So he was making that plate feel wide to those hitters. He was able to command that two-seamer on the corners late in the count for kind of a freeze fastball. He pitched well, that's for sure."
Houston center fielder Jordan Schafer said his team had no answer.
"I had a couple of good pitches my first at-bat, and then I don't think we saw another pitch to hit for a while," Schafer said. "He threw really well tonight, kept the ball down and threw the ball in and out and finished us off with a splitty or slider. Hats off to him. He threw outstanding."
Glenn Sattell is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.