HOUSTON -- Starlin Castro says he doesn't care where he bats in the lineup.
On Monday night, he certainly appeared to like the leadoff spot.
Castro had three hits and scored three runs, Byrd drove in a pair of runs and Barney hit an RBI triple as the Cubs jumped on the Astros early, building a 5-0 lead by the fourth inning. Alfonso Soriano drove in two runs with a double in the first.
"I don't care what spot," Castro said. "First, second, I don't care."
Cubs manager Mike Quade is encouraged with how his young players Castro and Barney have started the season.
"The kids did really, really well," he said. "I liked watching them. It's fun to watch them. They feed off of each other, and they play with enthusiasm."
"I felt good tonight," Dempster said. "Ninety-five percent of the time I felt like I was hitting my spots and making pitches."
Houston starter Nelson Figueroa (0-2) allowed eight hits and five runs in four innings.
"We know he is much better than that," Houston manager Brad Mills said. "He was just having problems today getting the ball over the plate and getting behind guys. But we've seen him and we know that that's not him and we know that he's going to be just fine."
Marmol later struck out Sanchez to end the eighth and allowed a hit and a walk in the ninth before striking out Joe Inglett to end the game.
Hall hit the sixth pinch-hit homer of his career with a solo shot to right field that made it 5-2 in the seventh inning.
Bourn followed with a double that bounced off the low wall in right field and back onto the field. Officials reviewed the play to see if it was a home run, but stayed with the original call.
Quade defended his decision to leave Dempster in after the homer by Hall.
"Dempster gave me every reason to," he said. "He was rolling along, allowing just one run. I thought we could get him through it. I liked the matchup with him and Sanchez. He made the mistake. I just didn't want him to lose it. That's what I was committed to. He had pitched too well."
The Cubs got to Figueroa early when Soriano's two-out, two-run double gave them a 2-0 lead in the first inning. Figueroa gave up a single to Castro and walked two of the first five batters he faced to set up the scores.
Castro got his second hit of the game on a single with two outs in the second inning. He scored on a triple by Barney that made it 3-0. Byrd's RBI single pushed the lead to 4-0.
Castro singled again in the fourth inning and gave the Cubs their first stolen base of the season when he swiped second. Chicago was the only team in baseball without a stolen base entering Monday's game.
He scored on a single by Byrd later in the inning to stretch the lead to 5-0.
"I'm frustrated," Figueroa said. "I hate losing, first of all. I hate putting our team behind in a situation like this."
Carlos Lee singled in the second inning before Dempster walked Brett Wallace. He got out of that jam by retiring the next three batters to end the inning and sat down the next nine overall, striking out five. He didn't allow another hit until Chris Johnson's single with no outs in the fifth inning.
Matt Downs drove Johnson in with a single that made it 5-1.
An error by Ramirez and two walks by Dempster loaded the bases for the Astros in the sixth inning. Dempster got out of the jam when Inglett grounded out to end the inning.
Chicago OF Kosuke Fukudome was out of the lineup Monday after straining his hamstring making a catch the day before. He is listed as day to day with the injury and the Cubs are hoping he will recover with a couple of days rest. "It's a delicate area because if you push that envelope it could become six weeks instead of four or five days," Quade said. "He's too valuable to just send him down and bring somebody else up right now. If we can get through this for a few days without having to DL him that will be huge." ... Houston RHP Alberto Arias, who missed last season after shoulder surgery and had tendinitis during spring training, threw to hitters on Sunday and is scheduled to do it again on Tuesday.