GREEN BAY, WIS. - An evening that began with some juicy Vikings quarterback drama at Lambeau Field ended with a sobering reminder of just how valuable stability at the position truly is.

The Green Bay Packers rolled to a 24-10 victory over the Vikings on Saturday in the first round of the NFC playoffs for two major reasons. One: They have Aaron Rodgers, the reigning MVP who continues to be a surgeon against almost about everyone he plays.

Two: The Vikings were forced to start Joe Webb, a wonderful athlete but a shaky passer who had only been on the field for three plays during the regular season.

The two-word translation: total mismatch.

Before Saturday, the prospect of Webb starting seemed unlikely. Christian Ponder had been limited in practice and was put onto the injury report as questionable Friday, still battling an elbow and triceps injury he suffered in last week's victory. But the Vikings were hopeful the tightness in Ponder's bruised throwing arm would subside and allow him to play.

It didn't.

Suddenly, with Ponder's limited range of motion pushing him onto the inactive list 90 minutes before kickoff, Webb became the emergency starter.

"It just wouldn't have been smart to put [Christian] in that position," Vikings coach Leslie Frazier explained. "Some of the things we asked him to do, he wasn't very good at getting them done. And he needed to be able to do them for us to put him out there."

And if ever, in an NFL playoff game, there has been a greater disparity between quarterback competency, it'd be difficult to find.

Rodgers, making his 85th career start including playoffs games, threw for 274 yards and one TD.

Webb? He hadn't throw a pass in a game since Aug. 30 in the preseason finale. And Saturday, on a brightly lit stage with a national TV audience, he demonstrated why the Vikings have firmly favored Ponder as their starter since last spring.

It wasn't only that the Vikings had only 6 net passing yards in the first half and didn't have a passing first down until midway through the third quarter, it's that so many of Webb's throws were way off.

His first pass, with pressure coming, bounced a yard short of Michael Jenkins. Later, a deep ball to Jerome Simpson sailed 4 yards too long.

A pass to Jarius Wright on an out-breaking route might as well have been intended for sideline reporter Michele Tafoya. And we haven't even gotten around to the inexplicable pass he threw straight up in the air on his second series while being hogtied by Erik Walden.

Or the lost fumble in the third quarter, forced and recovered by Clay Matthews. Or the interception by Sam Shields later that quarter.

"I thought we had some guys open," Frazier said. "But Joe might get flushed. Didn't get his feet set. Might not follow through like he needed to."

It was part of a rough night in which Webb was 11-for-30 for 180 yards.

Sure, Webb and Adrian Peterson (22 carries, 99 yards) led a 53-yard march for a field goal on the opening series. But that 3-0 lead never had much chance of holding up.

Not with Rodgers holding target practice, spreading the ball to 10 different receivers and commanding the offense with ease. In all, Green Bay scored 24 unanswered points.

The Packers' touchdown drive on their final first-half possession was vintage Rodgers. It began with a 22-yard connection to Jordy Nelson. Then 14 yards to Greg Jennings. Then a rollout right and an impossible-to-stop laser to Nelson for 23 more yards to the Vikings 3.

"Every time we play up here, he scrambles, makes some big throws," cornerback Antoine Winfield said.

John Kuhn's 3-yard run provided a 17-3 halftime lead. His 9-yard scoring catch on the first series in the third quarter inflated that advantage to 21 points.

Oh, and just in case fans needed old playoff scars reopened, Kuhn's TD catch came immediately after the Vikings were flagged for having 12 men on the field -- on fourth-and-4 with Mason Crosby lining up for a 32-yard field goal.

And that's how a remarkable 2012 season came unraveled at the end. With silly penalties. And a 3-0 deficit in the turnover battle.

With Peterson appearing at least somewhat stoppable. And with a bizarre Webb-for-Ponder change certain to generate a flood of reaction.

Soon enough, the Vikings will take pride in a turnaround that put them back in the playoffs, a 10-victory season providing proof that the current vision for building a winner is working. But as Rodgers demonstrated, quarterback excellence is a prerequisite for making that next leap.

Dan Wiederer dan.wiederer@startribune.com