Perhaps that's why the mashing, slugging Astros team that took the field Monday night looked nothing like the team that was held to three singles in a disheartening shutout loss to the lowly Pirates the day before.

The Astros rocked Chicago starting pitcher Carlos Silva for five runs and seven hits in the first inning -- tying Houston's season high for runs and hits in an inning -- and later got homers from rookies Jason Castro and Chris Johnson to blast the Cubs, 11-5, in the series opener at Wrigley Field.

"It's one of the things we're going by right now ... who cares what happened yesterday?" Johnson said. "And even tomorrow, who cares what happens? It's a new game, and we're going to try to go out there tomorrow and do the exact same thing."

Houston had a season-high 17 hits to go along with a season high in runs, with each player in the starting lineup getting at least one hit. That included pitcher Wandy Rodriguez, who went 2-for-3 for his first career multihit game. That included pitcher Wandy Rodriguez, who went 2-for-3 for his first career multi-hit game. The Astros had six extra-base hits.

"Carlos throws strikes, and I think they made a point to come out aggressive," Cubs first baseman Derrek Lee said. "He probably threw too many strikes tonight. I'm sure he'll make the adjustment. I thought his stuff was fine. He was just probably getting too much of the plate and they were aggressive and ready for it."

Johnson (3-for-5) was a double shy of the cycle and belted his first career homer in the seventh inning, and Castro went 2-for-5 with a three-run homer in the third. He's the first Astros catcher to have at least two men on base when he homered since a Brad Ausmus grand slam nearly four years ago.

"It's just one of those things," Castro said. "It's just a contagious thing. Everyone gets going and we were able to capitalize on some pitches today, and it seemed like everybody in the lineup was hitting the pitches they should be hitting, some of the mistake pitches. We did a good job of hitting them when we got them, and that's what happens when things are going well."

Silva, who threw seven scoreless innings against the Astros in April, allowed the first six batters of the game to reach and nine of the first 10. Hunter Pence had a two-run single with the bases loaded to drive in two runs, and Carlos Lee followed with a two-run double to make it 4-0.

"The guys were getting some quality at-bats, and that's the biggest thing," Astros manager Brad Mills said. "It's nice to see everybody pitch in up and down [the lineup] and have a balanced attack the way they swung the bats. The talent is there, and you know it's going to come out at some point, especially after [Sunday]."

Because of his team's struggles Sunday, Mills shuffled his lineup for Monday's game. He moved steady Jeff Keppinger out of the No. 2 hole and into the No. 6 spot to provide more offense at the bottom of the lineup, with shortstop Angel Sanchez moving to the second spot.

Sanchez went 3-for-6 with a double, and Keppinger was 1-for-2 with three walks and three runs scored.

"We had a lot of guys having good at-bats," Johnson said. "Whatever order we're in, we're just trying to go up there and have good at-bats. Because you're hitting in the No. 2 hole or in the No. 7 hole, that doesn't mean you're going to change too much. We had a bunch of guys on base and got some big hits."

Castro, the club's top prospect and playing at Wrigley Field for the first time, belted a three-run homer to right field in the third to stretch the Astros' lead to 8-0. He saved the ball after it bounced out of the bleachers.

"When I hit it, at first I didn't think it had a chance," he said. "In BP, the balls weren't flying very well, but kind of as the game went on, the wind started picking up and it looked like it would carry. It got out and gave us that cushion that took the pressure off a little bit and let us just play."

The Cubs scored once in the third and fourth innings off Rodriguez and then sliced the lead to 8-5 in the sixth on a solo homer by Tyler Colvin and a two-run homer by Aramis Ramirez. No lead is safe at Wrigley Field.

"It just seemed like the ninth inning took a long time to get there," Mills said.

But Johnson answered with a two-run shot in the seventh to make it 10-5. As a prank, his teammates defaced a baseball and gave it to him during the game and told him it was the ball he hit for his first homer. Roy Oswalt gave him the actual pristine ball when the game was over.

"They just destroyed it," Johnson said with a smile.

Rodriguez (7-11) didn't manage a quality start, allowing eight hits and five runs in six innings, but he still won for the fourth time in his past five outings. The two homers he allowed tied a season high, done twice previously.

"When I see the score 8-0, I felt comfortable," Rodriguez said.