"I said, 'To be a championship team, that's the games we need to win,'" Lee said. "We have the lead and need to play defense and hold them. That's not always going to happen, but we have to be 80-, 90-percent successful in these situations."
Lee's three-run homer in the fourth inning was the difference in the Astros' scintillating 3-2 win over the first-place Cardinals at Minute Maid Park, but Houston made several game-changing defensive plays, including double plays to end the eighth and ninth innings.
Brian Moehler (7-5) held the Cardinals to six hits and two runs in 6 1/3 innings to improve to 5-0 lifetime against St. Louis, and four Astros relief pitchers tiptoed around baserunners in the final three innings. The win pushed Houston to within three games of the lead in the National League Central.
"All around, it was a beautiful game," Lee said. "We pitched good, we played good defense and we got timely hitting. To be in contention, we need to beat teams like this in games like this."
The atmosphere at Minute Maid Park, which saw a spike in attendance (36,437), hinted of the playoffs and perhaps things to come in Houston. The next two games of the series figure to be just as electric, with the Astros sending their formidable 1-2 punch of Wandy Rodriguez and Roy Oswalt to the mound.
"We've had some good starts," manager Cecil Cooper said. "Our pitchers have really kept us going in a time when our offense has staggered a little bit. Our pitchers have continued to pitch well, and it's always good to get the first game of a series. You have to feel good with Wandy and Roy going the next two."
The list of heroes for the Astros on Monday was rather lengthy.
Shortstop Miguel Tejada made a terrific diving catch to his left to rob Nick Stavinoha of a hit with a runner at second base in the fifth, and Bourn capped the inning by running down a Ryan Ludwick fly ball to straightaway center onto Tal's Hill.
Moehler emphatically pumped his fist when the ball settled in Bourn's glove, and Ivan Rodriguez did some fist pumping after throwing out Albert Pujols at second base in the eighth. The slugger led off with a single and tried to advance on a ball that skipped away from the catcher.
"I think the one Tejada made, the diving catch, was huge," Moehler said. "That was a big play. We made some good defensive plays and turned a couple of double plays late in the game, and we got a big hit when we needed it."
The Houston bullpen, which coughed up the lead Sunday in Los Angeles, followed Moehler with 2 2/3 scoreless innings. LaTroy Hawkins gave up the game-winning homer Sunday, but redeemed himself by getting Yadier Molina to ground into a double play to end the eighth. Jose Valverde worked the ninth for this 10th save.
"I think we are a really good team," Lee said. "We don't get noticed for being a good team. We get noticed for being an old team. But we've got a good group of guys that knows how to play the game and have been on a championship team before and knows what it takes to go the extra mile."
Moehler retired 10 of the first 12 batters he faced before giving up three consecutive hits in the fourth inning, including a two-run single up the middle to Molina that scored Ludwick and Rick Ankiel and put the Cardinals ahead, 2-0.
"I left some pitches up, and they got some hits off them," Moehler said.
In the bottom of the inning, Tejada beat out an infield single and Lance Berkman walked to set the stage for Lee, who rocketed an 0-1 pitch from Cardinals starter Kyle Lohse (4-6) high over the wall in left field for a three-run homer and a 3-2 lead for Houston.
"Can't walk Berkman there," Lohse said. "I know he's a good hitter, but I made some really bad pitches. And then Carlos Lee. Whatever it is, he feels comfortable up there against me. The pitch was meant to be about eight inches inside, and it was only maybe three. And that's your ballgame."
Tejada said beating the Cardinals to open the series was huge.
"You never want to lose the first game," he said. "I think this series is going to be like that. Taking the first game is great, and I think we're taking it to a different level on defense and I think that will be the key for us in the second half."
Brian McTaggart is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.