Since taking over for Brad Childress in 2010, Leslie Frazier has won games in December of each season that have defined his tenure.

In 2010, he beat a good Eagles team on a dreary Tuesday night in Philadelphia in a game delayed two days by snow, signaling to owner Zygi Wilf that he knew how to inspire a team under the worst of circumstances.

In 2011, he coaxed the Vikings to the most franchise-damaging victory in recent history, as Adrian Peterson shredded his knee and winning kept the team from being able to draft Robert Griffin III.

Sunday at the Metrodome, on another snowy December day, Frazier earned his biggest victory as a head coach since he was running the upstart Trinity University program in the '80s and '90s.

"I am so very proud of our football team," he said.

The Vikings' 21-14 victory over Chicago means that the rest of December will matter, and that ...

• Adrian Peterson's pursuit of 2,000 yards could mean an MVP trophy for the best back in football. He rushed for 104 yards in the first quarter before settling for a measly 154. "Just keep handing it to him," said linebacker Chad Greenway. "He's unbelievable."

• This team has exceeded expectations. Few people outside the organization would have predicted more than six victories, or that this team would contend for the playoffs into mid-December. A 7-6 record and a victory over a division rival and playoff contender in December is a sign of growth for a team that was one of the worst in the NFL the previous two seasons.

• The division isn't as daunting as it appeared. Being 7-6, with two victories over Detroit, one over Chicago, with a competitive showing at Green Bay, indicates that the Vikings' roster compares favorably to their division rivals at every position other than quarterback and receiver.

• Frazier's job should no longer be a matter of public speculation. He has a winning record with a team incapable of making big plays downfield in what is supposed to be a passing league. He's capable of rallying a team and winning with a running game and a strong defense.

• The Vikings are no longer one of the worst pass-defense teams in the NFL. Rookies Harrison Smith and Josh Robinson produced key interceptions on Sunday, continuing their strong play. Left tackle Matt Kalil, Smith and Robinson are three rookies thriving at positions of great importance.

• Christian Ponder's continuing erratic play isn't the primary source of conversation in the Twin Cities. He threw for just 91 yards, tossed a silly interception and almost fumbled while inexplicably trying to throw a pass while being sacked, but winning meant not having to worry about getting benched even if he deserved it.

• The locker room won't become a depressing place. The Vikings' veterans, such as defensive end Jared Allen, would have had trouble caring much about meaningless games at the end of a third straight losing season. Winning Sunday means there is hope, and reason to care.

• Speeches by Allen and team owner Zygi Wilf were not for naught in a league where too many speeches are a sign of imminent trouble.

"I was just trying to express to the young guys that you don't get a chance to be in the playoffs very often," Allen said. "At least, I haven't. I've been three times in nine years. So for me that's the best kind of football. That's the only thing we play for.

"I don't think 9-7, 8-8 will get you into the playoffs this year. Even at 10-6 we might need some help. So we've got to keep winning. We've got to play more ball like this."

NFL players are used to guarding their emotions, used to the ebb and flow of a long season, but they knew this was their biggest game since 2009.

"We just wanted to play our hearts out," said defensive end Everson Griffen. "It was do or die today, and we did it. We came out victorious.

"And proud. Very proud."

Jim Souhan can be heard Sundays from 10 a.m. to noon and weekdays at 2 p.m. on 1500-AM. His Twitter name is SouhanStrib. jsouhan@startribune.com