The problem with Tebowing is everybody has their heads down and their eyes closed.

Otherwise, more people would see that Tebowmania doesn't even remotely exist without a Broncos defense that has played as well as any unit in the league the past month.

During a four-game winning streak that's turned the Broncos from 2-5 to playoff contender to leading NFL story line, quarterback Tim Tebow has never found himself down by more than two scores. When the quarterback position is played with the admirable but still primitive scrappiness of what's essentially a very fast fullback, sound team defense trumps one man's Divine Intervention.

That's not to say there isn't something magical about Tebow when the game is on the line late in the fourth quarter or overtime. But mentioning his comeback victories and his 5-1 record as a starter should include additional information such as elite defenders Elvis Dumervil and Champ Bailey returning from injuries to help the team U-turn from its 1-4 start.

"Their defense is keeping them in games," Vikings defensive end Brian Robison said. "And that's giving them chances to win at the end."

When Tebow took over for Kyle Orton, the Broncos ranked 31st in scoring defense (28.0). During their current four-game winning streak, they've allowed an average of 15 points per game. In their past three games, the Broncos have allowed 36 total points, second best in the league behind the 34 points that Houston has allowed.

"I think possibly the defense gets lost a little bit," Vikings running back Toby Gerhart said. "Everybody talks about Tebow and how he's continuing to win as a starter. But their defense is doing great things."

With their top pass-rushing lineman (Dumervil) and their top cover cornerback (Bailey) hobbled and/or out, the Broncos gave up at least 300 yards passing to three of the first four quarterbacks they faced this season. Since then, only one quarterback has thrown for 300 yards against them. And that was the Raiders' Carson Palmer, who also was intercepted three times in a 38-24 Denver victory at Oakland.

That victory started a four-week stretch in which the Broncos swept all three AFC West foes on the road. That includes a 17-10 victory at Kansas City and Sunday's 16-13 overtime win at San Diego.

The defense under first-year coach John Fox is displaying a lot of speed and confidence as it hits its stride heading into a December schedule that starts with Sunday's game against the Vikings (2-9) at Mall of America Field.

"They're just playing without thinking," Fox told reporters when asked about his defense. "The guys are reacting, just playing ball."

It's hard to believe that the Broncos and Vikings both posted the same 1-4 record on the afternoon of Oct. 9. The Broncos changed quarterbacks the following week. The Vikings waited another week.

Since the Broncos changed quarterbacks, they've allowed 120 points in six games (20.0). Since the Vikings changed quarterbacks, they've allowed 150 points in five games (30.0).

"Yeah, you have to credit their entire team for what they are doing," Vikings coach Leslie Frazier said. "I think five out of the last six they have won. That's a team deal when that happens, but you're right, it gets lost in the shuffle when Tim is playing as well as he is playing. Those wins have come under his leadership so he deserves a lot of the credit, but it sounds like the rest of their team has really picked it up as well."

One defender playing some possibly historic ball during Tebowmania is linebacker Von Miller, the No. 2 overall pick in this year's draft.

"Absolutely," Robison said. "Von Miller is having a great year over there. He's a heck of a pass rusher and doing a lot of things for them as far as schemes that they do with him and blitzing him off the edge and things like that."

Miller has 4 1/2 sacks during the Broncos' four-game winning streak. With 10 1/2 sacks on the season, he has a chance to break the league's rookie sack record of 14 1/2 set by Tennessee's Jevon Kearse in 1999.

If it happens, perhaps Tebow Time could share just a smidge of the adulation with Miller Time.

Mark Craig • mcraig@startribune.com