Starlin Castro hit three singles and crossed the plate three times, adding a stolen a base for the Cubs, who were coming off a series loss to Milwaukee.
Ryan Dempster (1-2) worked 6 1/3 innings, allowing four runs on six hits and three walks, while also striking out nine to earn the win.
“It was a good win,” Dempster said. “Any time you win the first game it’s huge. We had a lot of energy right out of the gate.”
Astros starter Nelson Figueroa (0-2) lasted only four innings, allowing five runs on eight hits with two walks and three strikeouts. He was 2-0 against the Cubs in 2010 with a 2.77 ERA in three appearances.
“I am not somebody that should be a work in progress,” Figueroa said. “I am frustrated. I hate losing and I hate putting our team behind.”
Soriano hit a two-out, bases-loaded double in the first to score Castro and Darwin Barney, giving the Cubs an early 2-0 lead.
After Castro singled with two outs in the second, Barney tripled and Marlon Byrd singled to make the score 4-0. Byrd added an RBI single in the fifth.
Houston had opportunities to score but failed to take advantage of them.
Cubs first baseman Carlos Pena dropped a potential double-play grounder with no outs in the bottom of the second to put runners on second and third with one out. But Joe Inglett struck out and Humberto Quintero grounded out to end the inning.
The Astros got their first run when Matt Downs’ pinch-hit single scored Chris Johnson in the fifth, but then failed to capitalize with the bases loaded and two outs in the sixth, as Inglett grounded out to second base.
That was the end of Dempster’s day, while John Grabow came in and got the final two outs of the inning.
Carlos Marmol entered the game in the eighth with two outs and runners on the corners and got Sanchez to strike out on a slider to end the threat. He then struck out Inglett with men on first and second with two down in the ninth to earn the four-out save.
“Our bullpen just did a great job,” Cubs manager Mike Quade said. “Grabow and Marshall both, it wasn’t beautiful but they go through it. Marmol go us through it at the end.”
Byrd is two doubles away from 200 for his career…The Astros’ Michael Bourn doubled to extend his hitting streak to six games…Houston went 3-for-12 with runners in scoring position and left 12 men on base.