CHICAGO – Houston’s Chris Sampson needed only 64 pitches for five shutout innings against the Chicago Cubs, who seem to be numbed by the cold – at the plate and in the field.

If Sampson’s calf muscle hadn’t tightened up while he was running the bases, he could have pitched a little longer on another windy day at Wrigley Field.

“Believe me I didn’t want to come out of the game, but for the long run it was the best decision,” Sampson said after the Astros’ 4-2 win. “It’s fine. Pitching, walking, all that doesn’t bother it. When I try to run on it that’s when it starts getting pretty sore.”

Sampson (1-0) allowed three singles in his fourth major league start, his first this season, and the Astros beat the Cubs for a second straight day. The game featured three errors by Chicago shortstop Cesar Izturis, a former Gold Glove winner.

“It was tough today. It’s part of the game, errors,” Izturis said. “You have to forget about today and come back tomorrow with a new mind.”

Getting a boost when the Astros scored three in the first inning, Sampson extended his scoreless streak against the Cubs to 12 innings dating to last season, giving up six hits.

And the starter’s role seems to suit him. In his first four major league starts, Sampson is 2-1 and has allowed just one earned run in 19 2-3 innings.

“Sampson did a nice job of making good pitches and our hitters put some runs on the board early,” Astros manager Phil Garner said. “They’re talking about Chicago’s offense hasn’t broken out. Well, our offense hasn’t broken out, either.”

Blanked on three hits through eight innings by Sampson, Rick White and Chad Qualls, the Cubs scored two runs in the ninth with four hits off Dan Wheeler. Derrek Lee and Mark DeRosa had RBI singles before pinch-hitter Matt Murton’s game-ending popout with two on.

Even before the loss, which dropped the Cubs to 3-5, Chicago manager Lou Piniella predicted the team would play better once the weather warms. It was 47 degrees Tuesday.

“I was telling our general manager today, the way we’re put together as a team, if we play in 40-degree (weather) all year, I don’t think we’re going to do very well because we don’t have that type of team,” Piniella said. “We have more power in our lineup. We need to bang it a little more, and once the weather warms up, we will.”

After the game, Piniella wanted to make sure his comments weren’t misinterpreted. He said the Cubs are more a fly-ball team than a small-ball group but still should be able to win cold-weather games.

In their first two games at home, the Cubs have managed five runs.

“We got to play in cold weather the same way the other team does, and we got to win our share of ballgames in cold weather, the same way the other team does,” Piniella said.

“Look, it’s not the easiest thing in the world to swing a bat in cold weather,” he said. “If you gave me my preference, hitting in 40-degree weather and hitting in 80-degree weather, I’m going to take 80-degree weather all the time. I know it’s a tough thing to do, believe me. At (the) same time, you have to be selective and got to make the other pitcher pitch, and I think that’s what we did in the ninth.”

Houston bunched four straight hits in the first inning to take a 3-0 lead against Jason Marquis (0-1). In his first start for the Cubs at Wrigley Field, Marquis allowed four runs, four hits and four walks in five innings. He is 1-4 in the Cubs’ home park.

On a day with the wind blowing in at 15 mph, Morgan Ensberg doubled with one out, Lance Berkman singled, Carlos Lee hit an RBI single and Luke Scott followed with a two-run double that went over Alfonso Soriano in center when the new Cubs star appeared to initially misjudge the ball.

“When I hit it, I saw him, he just kind of froze. The ball was hit right at him,” Scott said. “It had a little backspin and fortunately it was able to go over his head.”