DENVER – If this was an early test of their newfound identity after back-to-back wins, the Vikings fought hard but ultimately failed physically with black-and-blue colors.

Teddy Bridgewater was sacked seven times and lost a fumble with 29 seconds left, NFL rushing leader Adrian Peterson was stuffed on 15 of 16 carries, the defense gave up a 72-yard touchdown to the league's 31st-ranked rushing attack and Blair Walsh hooked a 38-yard field goal wide left.

Add it up and the Vikings lost 23-20 to the unbeaten Broncos in front of an announced 76,421 fans at Sports Authority Field at Mile High Stadium on Sunday.

"We had a chance to win," said Vikings coach Mike Zimmer, vetoing some players who argued that they should have won. "But I think we made too many mistakes to win."

The Vikings (2-2) erased a 10-point fourth-quarter deficit when they turned a Harrison Smith interception into Walsh's 33-yard field goal with 5 minutes, 11 seconds left. But the momentum of intercepting Peyton Manning a second time — and scoring 10 points off those picks — fizzled as the defense and pass protection struggled at the end.

Brandon McManus' 39-yard game winning field goal with 1:51 left capped a nine-play, 55-yard drive that included C.J. Anderson's 13-yard run into field goal range. Denver (4-0) averaged 6.0 yards per carry, 3.4 better than its league-worst 2.6 entering the game.

Yet the Vikings still had a chance to tie or win in the closing seconds. Bridgewater overcame a sixth sack to run for a first down on third-and-10, but Denver's seventh sack was a strip by safety T.J. Ward and a recovery by linebacker Von Miller at the Vikings 42-yard line.

"We still have room to grow," said running back Adrian Peterson, who had a 48-yard touchdown on fourth-and-inches but only 33 yards on his other 15 carries. "I love the way guys fought, being down [10-0 and 20-10]. … There is a lot to look back on. But I think we're OK. We'll be good."

The Vikings fell to 2-8 on the road under Zimmer. But they now get a bye week followed by a game against Kansas City at TCF Bank Stadium, where they are 7-3 under Zimmer.

So 2-2 at the bye has to be somewhat satisfying. Right, Harrison?

"No," Smith said. "It's average. It's just as bad as it is good. But as long as we build and continue to get better, there's a lot of football to be played."

The Vikings did a number of things against Denver as well if not better than any other team has this season. They won the turnover battle (2-1) against a team leading the league in turnover differential. They converted six of 16 third downs (38 percent) against the league's top third-down defense, which had allowed its first three opponents to convert only six of 38 third downs (18.8 percent).

And they outscored Denver in points off turnovers 10-0, including a 4-yard touchdown pass to Mike Wallace that was set up by linebacker Anthony Barr's 32-yard interception return 23 seconds before halftime.

The score closed the Vikings' deficit to 13-10 at the half. But it wasn't enough to overcome a slow start that included two 13-yard sacks in Bridgewater's first four pass attempts and three sacks for 34 yards in the game's first two series.

"I don't think we played very well offensively in the first half," Zimmer said. "But we were able to fight back and make some plays, keep going and hanging around. Our guys kept fighting. It could have been ugly, but we have a lot of fighters."

The Vikings entered Sunday with a No. 3-ranked running game that had rushed for 362 yards the previous two weeks. But Zimmer told the team he was going to be aggressive. The Vikings came out throwing the ball and ended up with 41 passes and 21 runs.

Zimmer's aggressiveness paid off with a conversion on fourth-and-1 in Vikings territory and the Barr interception, which followed a Zimmer timeout with Manning facing third-and-10 with 40 seconds left in the half.

"I told them last night in the meeting that I was going to be aggressive and we were going to go for it when we had the opportunities," Zimmer said. "They were all for it. Sometimes you got to play that way. But I'm disappointed because I know there were a lot of things we could have done better. If we had done those things better, I think the outcome of the game would have been different."

Mark Craig • mcraig@startribune.com