PITTSBURGH — Couldn't have been more perfect.

Ben Roethlisberger was the big-game quarterback the Pittsburgh Steelers waited 20 years to find, shredding Denver's defense with numerous key first-half throws and stopping the franchise's lengthy run of AFC championship game failures.

Elway, Bradshaw or Brady couldn't have done it any better.

Jerome Bettis ran for his last NFL touchdown. The defense repeatedly pressured quarterback Jake Plummer into mistakes or sacked him, forcing four turnovers while not allowing a Denver runner to gain more than 36 yards.

When it was over — and it effectively was when Pittsburgh led by 21 points at the half — the Steelers' 34-17 victory completed their 3-for-3 road sweep during the AFC playoffs. It also set up their less-impressive but oh-so-meaningful 21-10 win over Seattle in the Super Bowl.

Now, the Steelers are wondering where all the good times and big plays have gone.

With the Broncos (5-2) coming to Pittsburgh on Sunday for the first time since winning an AFC title there in January 1998, the Steelers (2-5) have matched the worst start by a defending Super Bowl champion in 19 years.

They've come close to replicating the quality of play in that AFC championship game only once, a 45-7 rout of Kansas City on Oct. 15 that is their only victory in six games. Whenever Roethlisberger seems to be finding the groove he located during that eight-game winning streak that ended last season, he seems to get hurt.

Super Bowl title or not, the Steelers have lost eight of their last 14 regular-season games, even while going 28-11 since 2004. They have admittedly reached a desperation stage of a season that may require a stretch run like that of a year ago merely to reach the playoffs.

"We don't have any room for error, so it's almost a situation where this is it," cornerback Bryant McFadden said. "Last year, this was for the Super Bowl; this year is to live for another day."

The Steelers seemed to be in a state of denial about how badly their season was going until they lost 20-13 to Oakland last weekend, one of their worst defeats — given the perceived quality of the opponent — of coach Bill Cowher's 15 seasons on the job.

Roethlisberger's four interceptions weren't the only culprit; the Steelers couldn't score after having a fourth-and-goal at the Raiders 1 with less than three minutes remaining. When Bettis was around, such situations usually represented automatic scores.

"All I know is that over the last three games, they've averaged 430 yards and 31 points," Broncos coach Mike Shanahan said. "That's pretty productive."

Shanahan also said, "They're not a 2-5 football team."

That's what puzzles the Steelers. Are they the team that won the Super Bowl, or that which lost to awful Oakland? Is Roethlisberger the quarterback he was last season, or last weekend? Are they the team that beat the Chiefs by 38 points, or the one that could barely gain a yard in the second half against Jacksonville and San Diego?

Roethlisberger looked to be back to where he was last season, throwing five TD passes and no interceptions against the Chiefs and Falcons, only to sustain his second concussion this year during the second half in Atlanta. He was rushed back for Oakland, yet played so poorly that Broncos lineman Ebenezer Ekuban pleaded with Cowher to start him again and not go to backup Charlie Batch.

"Maybe his confidence is low and he doesn't feel that energy around him," Ekuban said.

Cowher agreed the Steelers have no right to feel confident.

"We haven't done the things we need to win football games," he said, pointing to an alarming 18 turnovers in seven games.

This week, the challenge is a Denver defense that was on pace for one of the best seasons in NFL history — two touchdowns allowed in six games — until Peyton Manning threw three touchdown passes to Reggie Wayne in the Colts' 34-31, last-minute decision last Sunday.

Regardless of how well or not so well their defense plays in Pittsburgh, the Broncos understand Plummer must play better than he did in the AFC title game for them to win the rematch.

"I'm tired of talking about last year," Plummer said. "I'm one that moves on, and I didn't have a good game. It's a new season. If I sat here and cried about it, I wouldn't get anything done."