PITTSBURGH — This is exactly why the Minnesota Vikings spent the summer trying to persuade Brett Favre to end his latest retirement: to run their offense, not be their offense.

To show them how to win big games, especially those in difficult road settings such as Pittsburgh. To complete the passes that must be completed, to win the games that simply can't be lost.

They wanted him to be Ben Roethlisberger.

There are numerous subplots to Sunday's important game between the unbeaten Vikings (6-0) and Pittsburgh Steelers (4-2), one that matches a team playing like a champion against one that's proven twice in the last four seasons it is a champion.

Can NFL rushing leader Adrian Peterson, called by Steelers coach Mike Tomlin the best football player in the world, break off runs against one of the best defenses of its era? Can a getting-healthy Troy Polamalu disrupt one of the league's best-balanced offenses? Can the Steelers' improved offensive line handle the Vikings' run-controlling defensive front?

Ultimately, it may come down to what nearly everyone wants to see: Can a still-young quarterback who's already won two Super Bowls prevent an ageless quarterback he admired as a youngster from taking a small but significant step toward winning his second?

Even more intriguing is that while Roethlisberger spent his first five seasons mostly managing the Steelers' offense, he's quickly transforming himself into a modern-day version of Favre.

"They are playing to their quarterback," Vikings coach Brad Childress said. "He's (Roethlisberger) obviously come a long way from making eight throws in a game and handing the ball off. I don't think they are that type of football team. They are not trying to deceive."

Roethlisberger leads the NFL in yards passing, something no Steelers quarterback has done for a full season since the 1970 merger, and has three 300-yard games this season. Hall of Famer Terry Bradshaw had only four during his entire Steelers career.

Asked if the 27-year-old Roethlisberger reminds him of Favre, Childress said, "A young Brett Favre."

"I grew up watching Brett and idolizing him and molding a little bit of my game after him," Roethlisberger said. "It will be fun to play against him for the first time. He's a legend and I'm just trying to get to his level."

Curiously, at the same time, the 40-year-old Favre is becoming more like a younger Roethlisberger, a player whose most impressive statistic is his winning percentage, not his completion percentage.

With Peterson around, Favre doesn't need to chuck the ball carelessly and recklessly — he has 12 touchdown passes, only two interceptions and a 109.5 passer rating, his best such numbers at this stage of a season. He's proving a quarterback doesn't need to lead by arm alone; he's never been 6-0 in his career before, and now he has a chance to be 7-0.

"I've just practiced and gone about it as (if) I was 25," Favre said.

Played like it, too.

"I guess in some ways I would have thought we would be 6-0," Favre said. "Maybe not quite the way we have. I knew we could run the ball. That has been obvious. I didn't think we would be as productive in the passing game."

Productive enough that, while Roethlisberger was throwing for 417 yards during a 27-13 victory over Cleveland last week, Favre was passing for 278 yards and three touchdowns to help the Vikings beat the Ravens 33-31. Sidney Rice made six catches for 176 yards.

Steelers linebacker LaMarr Woodley, 24, finds it remarkable Favre is playing much like he did when Woodley was starting grade school.

"He's still making plays today like he was then," Woodley said. "That's helping this team win."

Winning in Pittsburgh might be the toughest assignment the Vikings have given Favre so far. The Steelers have won their last nine there and, after a brief letdown in which they lost to the Bears and Bengals following Polamalu's knee injury in the season opener, they've won their last three overall.

Rashard Mendenhall gained 304 yards and scored four touchdowns during those three victories, while Roethlisberger threw for 1,027 yards and seven touchdowns, easily the best such stretch of his career.

Mendenhall, who has made only four career starts, will be running directly at 317-pound Pat Williams and 311-pound Kevin Williams, the Pro Bowl tackles who helped the Vikings lead the NFL in rushing defense the last three seasons.

"They've been No. 1 at stopping the run for a long time, and the one thing we wanted to pride ourselves on this year is getting the run going," Steelers right tackle Willie Colon said. "I think we've been pretty good at it so far and if we can run on these guys, it will be kind of a warning shot to the NFL that we can."

Favre doesn't know where this 6-0 start will take the Vikings. He might have a better idea after going against a Pittsburgh defense that led the league the last two seasons and is capable of making any quarterback feel like he's 40, much less one who is that old.

"This (Steelers) scheme makes it so hard to prepare. It's pretty stressful. You're sitting there going, `A-h-h-h,' " Favre said, gripping a table and shaking it. "At times you play into their hands, and that's what they want you to do. It really comes down to making plays when they are there. You get limited opportunities against a team like this."