In convincing fashion, the Cards eliminated the Brewers, securing their spot in the World Series, which begins against the Rangers on Wednesday at Busch Stadium.
Tunnel vision is working for the Cardinals, who haven't had time to reflect on their improbable playoff run.
"One of the keys is you can never allow yourself to look back, because that's a distraction," said La Russa, soaked in champagne in the elated Cards clubhouse. "When we went around to the different players, it was always about retaining your edge.
"Even for a minute, if you look ahead or look back, you lose edge. These guys were absolutely relentless about that. They were like, 'Today, today is the last game of our lives.' "
La Russa was taking no chances in a clinching situation.
From the beginning, the Cardinals were in control, scoring four runs in the first inning off Shaun Marcum. But the Brewers, who have plenty of firepower, chipped back with a leadoff homer from Corey Hart in their half of the first. And in the second inning, St. Louis starter Edwin Jackson gave up homers to Rickie Weeks and Jonathan Lucroy.
All series, La Russa pulled the right strings, and Game 6 was no different.
St. Louis was ahead, 5-4, after two innings, and La Russa felt Jackson had enough, so he pinch-hit for his starter in the third. Even that decision paid off, as pinch-hitter Allen Craig slapped a two-run single to center.
Once again, La Russa leaned on his heavily used bullpen. Relievers picked up the final seven innings, allowing two runs on three hits, while striking out seven and walking one.
The Cardinals used five relievers in Game 6, and lefty Marc Rzepczynski -- one run in 2 1/3 innings -- was credited with the victory.
"I had no idea I was coming in the fifth inning," Rzepczynski said. "When that [bullpen] phone rang, don't be surprised of anything."
Obtained from the Blue Jays in July, Rzepczynski now has the distinction of being the winning pitcher in the NLCS clincher. Sunday was also his first win as a Cardinal.
"If you would have asked me three weeks ago, never would I have thought my first Cardinals win would come in the clinching game," he said.
It's only fitting that a reliever was involved in the decision, because the bullpen was the story of the series. St. Louis' bullpen actually tossed more innings than the starters -- 28 2/3 to 24 1/3.
According to the Elias Sports Bureau, Redbirds relievers combined to pitch in 54.1 percent of the innings in the series. That's the fifth-highest percentage ever in an LCS, and the most since the Mets in 1999.
Cardinals relievers combined for a 1.88 ERA, offering a huge boost to a rotation that posted a 8.13 ERA. The longest outing by a St. Louis starter was five frames, by Chris Carpenter in Game 3.
"It's just a freak, weird postseason so far," La Russa said. "It's very possible in the World Series you will see the starters take charge, and things will get back to normal. That's kind of defined the postseason so far, and we're fortunate to have a good bullpen."
As lock down as the relievers have been, La Russa still was uneasy in the ninth inning with his team ahead by six.
"When it was 12-6 in the ninth, I was sweating bullets," La Russa said. "The Brewers are a very good and very dangerous team. It's not fun."
The Brewers weren't having a good time either, as their last hit was by Carlos Gomez leading off the fifth.
The ninth inning was more of the same, as Motte retired the side in order, handing the Cardinals their 18th pennant. For Motte, recording the final outs wasn't a problem. It was how to celebrate that was a bit awkward. After the strikeout, he walked slowly towards home plate and looked at catcher Yadier Molina.
Eventually, Molina widened his arms, and the two embraced.
"It was one of those things, when I was out there, I didn't know what was going to happen," the right-hander said. "I was going out there, and my job was to get guys out and win tonight's game. I went out there and got 1-2-3, and on that third strike, I didn't really know what to do."
On Saturday night, Motte watched the Rangers eliminate the Tigers, and he saw their celebration.
"I remember I was watching the Texas game, and I saw them get that third out, and I was getting goosebumps sitting in the restaurant," Motte said. "I was like, 'That had to be an awesome feeling.' To be out there and be able to be in that situation. Yadi throwing his hands up, I don't remember much after that but Yadi hugging me and me hugging him."