MILWAUKEE -- On the eve of the most significant start of his life, Shaun Marcum did not seem stressed about the struggles he has endured over the past five weeks. Instead, the Brewers' right-hander seemed to be at ease as he prepared to spend Saturday night relaxing with his father and his brother.

"I'm not going to put pressure on myself 24 hours before the game starts or anything like that," Marcum said. "Just staying relaxed. My brother is coming in. My dad is here. So we'll probably just hang out at the house and watch some football."

Marcum is well aware of what's at stake when he opposes Edwin Jackson and the Cardinals in Game 6 of the National League Championship Series on Sunday at Miller Park. With the Brewers facing a 3-2 deficit in this best-of-seven series, there is absolutely no margin for error.

A loss will end the Brewers' season. A win over the Cardinals will set up a winner-take-all seventh game to determine which of these teams advances to the World Series.

Tale of the Tape: Game 6
2011 Regular Season
Overall: 33 GS, 13-7, 3.54 ERA, 57 BB, 158 K
Overall: 31 GS, 12-9, 3.79 ERA, 62 BB, 148 K
Key stat: .232 opponent BA in regular season; .378 in postseason
Key stat: 10 quality starts in 14 outings since arriving in St. Louis
At Miller Park
2011: 17 GS, 5-4, 4.81 ERA
Career: 18 GS, 5-5, 4.87 ERA
2011: 2 GS, 1-1, 5.79 ERA
Career: 2 GS, 1-1, 5.79 ERA
Against this opponent
2011: 5 GS, 1-2, 5.10 ERA
Career: 5 GS, 1-2, 5.10 ERA
2011: 4 GS, 1-1, 4.80 ERA
Career: 6 GS, 2-2, 4.21 ERA
Loves to face: Lance Berkman, 1-for-17
Hates to face: Nick Punto, 5-for-13
Loves to face: Prince Fielder, 3-for-15
Hates to face: Jerry Hairston Jr., 7-for-13
Game breakdown
Why he'll win: Hasn't lost three straight decisions since 2006
Why he'll win: 4-0 with a 3.10 ERA in nine starts dating back to Aug. 20
Pitcher beware: 0-2 with a 12.46 ERA in two postseason starts, incl. Game 2 loss
Pitcher beware: Allowed seven hits and walked a batter in just 4 1/3 IP in Game 2
Bottom line: Time for redemption
Bottom line: Just keep rolling
"Definitely a big game, but it's baseball," Marcum said. "It's another game. You just gotta take it at that. We can't put too much pressure on ourselves. We just gotta go out there and play the game, play the game the right way, do what we've done all year."

Unfortunately for Marcum, the results he has generated over the past five weeks have not resembled those he created while posting a 3.11 ERA and limiting opponents to a .218 batting average in his first 29 starts of this season. In his past six starts, including two playoff outings, the 30-year-old has posted an 8.18 ERA and allowed opponents to hit .341 against him.

But when forced to make the biggest decision of his first season as a Major League manager, Ron Roenicke never seemed to waver with his support of Marcum. Instead, Roenicke has spent the past week saying that his veteran hurler has pitched much better than recent results indicate.

"I don't expect him to stay where he was the last few games," Roenicke said. "I still don't think that he's pitched as bad as what those numbers are. We make some plays for him, and those numbers change quite a bit."

When Marcum allowed the Cardinals five earned runs in just four innings in Game 2 on Sunday, he was doomed by Albert Pujols, who hit a two-run home run in the first inning and a two-run double in the third. Brewers center fielder Nyjer Morgan missed a fly ball in front of both of those extra-base hits.

After the game, Marcum was not placing blame on Morgan or playing the "woe is me" role. Instead, it seemed like he was already looking forward to his opportunity to return to the mound and reward the loyalty that Roenicke has shown.

"I think they felt that they're comfortable with me going out there, and, you know, it's nice to have that kind of support," Marcum said.

Roenicke and the Brewers have reason to continue believing in Marcum, who has allowed three earned runs or fewer in three of the five starts he made against the Cardinals this year. His finest outing against St. Louis was completed on Aug. 30, when he allowed just two unearned runs over seven innings.

That was also one of the best home starts Marcum -- who led the Majors with a 2.21 road ERA -- produced this year.

"I think he's a guy that understands how to pitch," Roenicke said. "I think he got out of his game a little bit the last couple games he's pitched. And I think he'll figure some things out."

While spending the previous four seasons with the Blue Jays, Marcum endured his share of rough stretches while having to face the Yankees and Red Sox on a regular basis. He believes this might have helped him remain confident while enduring stretches like this one.

"Baseball's a weird game," Marcum said. "You can go out there and pitch well against some teams, and you can go out there and get hammered by some. That's just how this game works. Confidence is still as high as it's ever been. It's just a matter of going out there and making pitches, and locating them and trying to get some outs."