Apparently, in a schizophrenic season -- encouraging early, then maddening, now just puzzling -- the Vikings felt a pressing need to treat Week 14 as message delivery time.

First it was the veterans, salving the sting of last week's loss in Green Bay by issuing frequent reminders that the season was far from finished.

Said Jared Allen: "I've tried to express to these young guys, you don't get the chance to go to the playoffs very often."

Then it was owner Zygi Wilf attending Friday's practice at Winter Park and feeling compelled to deliver his own sermon about Sunday's contest with Chicago.

"He wanted us to understand what this game meant," center John Sullivan said. "And he wanted to reiterate the ownership's commitment to our success and how much they want to win. That's big."

And then came Leslie Frazier's pep talk to the newbies, with the head coach gathering his young players and letting them know that by December in the NFL, inexperience can no longer be used as a convenient excuse for failure.

"You can't hide behind the fact that you're a rookie anymore," Frazier said.

So how do we explain the Vikings' 21-14 win over Chicago on Sunday at Mall of America Field? Well, in many ways, it was evidence that all the messages that circulated hit home.

The veterans wanted urgency. Well, how about Adrian Peterson's electric 51-yard run on the game's first play, the catalyst of a touchdown drive that put the Vikings ahead to stay barely 3 minutes into the game?

Wilf wanted to inject passion. And the Vikings' defense responded accordingly, delivering an effort that was far from flawless but still energized throughout.

And Frazier? His call for the rookies to play like veterans was answered by defensive backs Josh Robinson and Harrison Smith, who both provided game-changing interceptions.

Robinson returned his first-quarter pick 44 yards to the Chicago 5, gift-wrapping a TD drive that provided a 14-0 lead.

And Smith left even less to chance, intercepting an airmailed Jay Cutler pass at his own 44, then weaving and winding all the way to the end zone with 3:27 left in the third quarter.

"Once I got my hands on it, I wasn't necessarily thinking end zone," Smith said. "But I was saying to myself, 'I'm not getting tackled. No matter what, just keep going.' "

That was the perfect mindset for a 23-year-old safety to have when his team badly needed a big play and didn't care where it came from.

It also allowed Smith to deliver his own message: Make way for the kids.

"The fact that we've had to play a lot of young guys early," Frazier said, "you hope that's going to pay dividends in the month of December. I think it's beginning to show."

Say what you want about these Vikings. Sure, they might still have serious worries about their passing attack, the NFL's worst and still in critical condition after Christian Ponder wobbled to an 11-for-17, 91-yard, one-interception day.

And yeah, they're still inconsistent, winning Sunday despite being outgained 438-248. But one thing has become obvious. From the ruins of 2011, many of the overhauls and improvements to this team are undeniable.

Plus, this year the season's final three games will have some meaning.

It hasn't hurt the Vikings to have one of the game's all-time greats in their backfield, running with amazing vision and purpose. And Peterson starred again Sunday, reaching 100 yards before the first quarter ended.

The Vikings ran 15 plays in the opening period. Twelve were handoffs to Peterson, who trampled a decimated Chicago defense playing without linebacker Brian Urlacher, tackle Stephen Paea and cornerback Tim Jennings.

By day's end, Peterson had a career-high 31 carries and 154 yards, even as Chicago continued to crowd the line of scrimmage.

"It's all willpower, man," Peterson explained.

Added Frazier: "You know when you play the Vikings you're going to have to stop Adrian Peterson. To be able to rush for 100 yards in the first quarter, just an amazing feat."

Sure, Sunday's effort wasn't all that pretty. Bears receiver Brandon Marshall kept getting loose and finished with 10 catches for 160 yards. And, heck, the Vikings had more interception return yards (100) than yards from their receivers (78).

But with the way this team is being built -- to succeed with a punishing running game, few turnovers and tide-turning defensive plays -- Sunday's win proved heartening.

"We won the way we're designed to win," Frazier said.

And that's a message this team is certain to take forward.

Dan Wiederer • dan.wiederer@startribune.com