Shortly after finding out that Bagwell will be out at least three months, Ensberg hit three home runs and Brandon Backe pitched a four-hitter for his first major-league shutout, leading the Astros to a 9-0 victory over the San Francisco Giants on Sunday night.
"I think it's going to affect the ballclub a great deal," Ensberg said. "I think a lot of people don't understand what Jeff Bagwell's presence in the lineup means to us."
Ensberg hit a three-run homer in the first inning off Jeff Fassero, a solo homer off Jeremy Accardo in the fifth, and another solo shot in the seventh off Jason Christiansen in the 11th three-homer game by an Astros player.
The last to do it had been Richard Hidalgo on Sept. 3, 2003, against Colorado.
"This certainly was my best game in the big leagues. I was getting the right pitches, seeing the ball well and getting the right swing," Ensberg said. "It was really a fun game."
Bagwell had a pair of three-homer games in 1999, but he has been robbed of much of his power because of the degenerative shoulder condition and has just three homers. He was placed on the disabled list Tuesday and the team announced Sunday that he will have surgery next month.
Bagwell's rehabilitation is expected to last three months. In the meantime, the Astros -- who entered with an NL-low .243 batting average -- could use more performances like Ensberg's.
"I hope we are a team that can take the momentum from tonight and start winning more games," Ensberg said. "That's what this is all about."
Backe (3-2) didn't allow an extra-base hit while throwing 114 pitches in the first shutout by a Houston pitcher since Roy Oswalt against Montreal last Aug. 6. Backe walked two and struck out six.
The Giants didn't have a hit until the fourth, when Omar Vizquel led off with a single. The closest San Francisco came to scoring was in the fifth, when Marquis Grissom walked and reached third with two outs on pinch-hitter Michael Tucker's single. But Backe got Jason Ellison to ground to third.
"Early on, I didn't feel that great, but as the game went on I started to realize that something really good could happen," Backe said. "It was the best game I've had and it was nice to get that shutout under my belt.
"I made some bad pitches, but I kept the ball down and I got away with them."
Fassero (0-1) pitched three innings and gave up five runs and five hits in his second start of the season.
After jumping ahead on Ensberg's home run in the first, the Astros increased their lead to 5-0 in the third on Craig Biggio's two-run homer, his seventh of the season and fourth in four games.
"He was definitely locked in tonight. He didn't miss anything," Fassero said of Ensberg. "The scouting report said to try to throw strikes on the outer part of the plate against him, but he just went the other way with them."
Backe had an RBI single in the fifth after Ensberg's second homer.
Houston manager Phil Garner missed Sunday's game with flulike symptoms. Cecil Cooper assumed his duties.
- Houston's 5-17 record against the Giants at Minute Maid Park is its worst against any NL team since moving to the park in 2000.
- Fassero is the third-oldest pitcher to start a game for the Giants at 42 years, 125 days. Warren Spahn was is the oldest at 44 years, 156 days in 1965, followed by Danny Darwin at 42 years, 310 days in 1998.
- J.T. Snow returned to the Giants lineup after missing eight games with an intestinal disorder. Backe is 7-1 in Minute Maid Park.