"You've got to get what you deserve," said La Russa.
Jim Edmonds and Larry Walker did most of the damage. Walker singled twice and drove in two runs, while Edmonds had two doubles, a run and an RBI. David Eckstein also scored twice and added an RBI double.
The Cardinals turned two double plays and played sharp defense, ran the bases well and generally played a game that looked a lot like many of their 94 other wins this year.
"I thought it was exactly the game that we played over and over again," said La Russa. "Our starting pitcher was outstanding, and when he had guys on base, he made pitches. Defense was outstanding.
"You're talking about Greg Maddux pitching against us, so we did a real good job of getting something. We got them over and got them in. The guys at the top, Larry had a [heck] of a day, Eckstein, Jimmy ... clutch production. We played this game over and over again many times."
Mulder dodged trouble again and again, and eventually outdueled Maddux. He permitted one run on eight base hits over seven innings, inducing 15 ground-ball outs against just three in the air.
It was the sixth straight game in which Mulder lasted at least seven innings and allowed no more than two runs. Yet he had been winless in his last three starts, thanks to a combination of meager offensive support and some bullpen troubles.
"Mulder really deserved this game today, because he's probably had the opportunity, or been in position, to win four or five games that we let get away from us after he's been out of the game," said pitching coach Dave Duncan. "It's nice for him to get a special win, and I know this is special for him."
The Cardinals won their 95th game of the season, giving them an even 200 since the start of 2004. Second-place Houston has 69 losses. The Cardinals had already assured that they would be division champions, if only by way of a tiebreak, but Saturday's win made it a certainty that they will finish with a better record than the Astros.
"If you had your preference, obviously to win the game that gets us there is kind of a dream come true," said La Russa. "The Cubs have just played us so tough all year long, and you have Maddux going against you, you knew it was going to be a hellacious ballgame. And it was."
Walker singled to right in the first inning to score Eckstein, who had singled, for St. Louis' first run. Mulder's first sacrifice bunt of the year was a squeeze in the second that made it 2-0, and Walker's third-inning single brought home Edmonds for a 3-0 advantage. Edmonds had doubled, then took third base on a ground ball to third, setting him up to score on Walker's single.
"Any time you get to contribute, it's a blast," Walker said. "No matter how big or small it is. There were a lot of things that happened in the game today, like Jimmy taking third on a ground ball to Nomar [Garciaparra]. That doesn't happen very often. It's little stuff like that. [Abraham] Nunez beats out a double-play ball and ends up scoring.
"Great things happened in the game today, and it happens every day. The obvious stuff gets looked at, and the not-so-obvious doesn't. I'm looking at the not-so-obvious."
Jeromy Burnitz clocked a solo homer off Mulder in the sixth, but when the Cubs got runners on base, they couldn't make headway against the left-hander. Chicago put a runner on in every inning, but stranded eight men and went 0-for-9 with runners in scoring position.
It was a pleasant turnaround for Mulder, who took the loss in two previous starts against Maddux.
"Everybody here has a lot of respect for him and what he's done in his career," Mulder said. "To win a game like this, as important as it is, against a guy like that, it's a tough game. But we did a good job."
Cardinals fans stuck around Wrigley Field long after the game ended, celebrating -- and celebrating with -- their heroes. Several players ducked out into the crowd and doused fans with beer, champagne and water as the faithful cheered them on.