What was this look on Leslie Frazier's face late Sunday afternoon as he glanced down and closed his eyes briefly to get his bearings?

The Vikings coach sure looked like a 13-year-old kid who had spent the previous three hours strapped into the Tilt-a-Whirl at Valleyfair.

Dizzied. Disoriented. Ultimately defeated.

Receiver Percy Harvin wore a similar expression, appearing as if he had just washed down two trays of nachos with an extra-large Slushee and then opted to take 10 consecutive rides on Steel Venom.

Here, after an exhilarating and entertaining afternoon, Harvin now felt sick to his stomach.

The Vikings lost yet again Sunday, this time 35-32 to the Tim Tebow-led Denver Broncos. The fun ended with Matt Prater's 23-yard field goal as time expired.

"Disgusted," Harvin said. "There are too many times this year when we've come in here and been left repeating ourselves. The letdowns, the missed assignments. This is another game we felt we had control of and somehow it slipped away."

With 1:33 to play, the Vikings had the ball in a tied game -- with overtime seeming like a worst-case scenario.

Then came a luckless turn of events, a pass from rookie Christian Ponder to Harvin seized instead by Broncos cornerback André Goodman at the Vikings 35 and returned to the 15.

This time, Tebow didn't need any final-drive heroics. He simply handed off four times, knelt once, let Prater close the deal and walked out of Mall of America Field with the oversized stuffed animal slung over his shoulder.

You have to be kidding, right?

It's not just that Denver is 6-1 with Tebow as its starter. It's that the Broncos have claimed three of those victories on game-ending field goals and a fourth on a final-minute Tebow touchdown run.

On Sunday, the Broncos won despite managing only 48 yards and one first down in the first half. They triumphed even after their usually reliable defense was shredded by the Vikings for 489 yards.

If you like twists and abrupt turns and fireworks shows, then Sunday's game was all sorts of stimulating with five turnovers, 10 second-half scores and plenty of fourth-quarter drama.

If you were a Vikings coach, however, every positive development seemed to be negated by a costly mistake.

As good as Harvin was, making eight catches for a career-best 156 yards with two touchdowns, Demaryius Thomas also wanted his time in the highlight package. Denver's young receiver had 144 receiving yards and twice broke through busted coverage for second-half touchdowns.

Ponder? He played brilliantly at times, amassing 381 passing yards and bouncing back from a rough start. But all told, his three turnovers cost the Vikings 13 points.

Ponder's final throw was simply a poor choice, a failed attempt to lure Goodman down to cover Stephen Burton on a shorter route.

"I got a little too greedy," Ponder said.

It was also Ponder's ninth turnover in six starts, rookie growing pains that seem to be growing sharper.

"Everybody talks about it -- rookies are going to have their ups and downs," Ponder said. "And obviously it's so. But it's hard for me to hear that. I don't want to go through ups and downs. I just want to go through ups."

On the other side of the ball, the Vikings defense is doing its own soul-searching. A unit that registered a safety on its first play and delivered two first-half takeaways Sunday crumbled like a stale corn dog in the second half.

After halftime, Willis McGahee rushed for 85 yards on 12 carries. Tebow went 6-for-9 for 173 yards after the break.

His 41-yard scoring strike to Thomas came on Denver's first play after a Harvin touchdown gave the Vikings a 22-14 lead. It also came thanks to a mad scramble that had a half-dozen Vikings charging Tebow while Thomas was left alone in the middle of the field.

"Tebow did good things," defensive tackle Kevin Williams said. "You can't take that away from him. But we all know he's not the greatest passer. And you can't give up [202] yards to him. I love the guy. And he does a lot of good things. But there's no way you can let that happen."

Several times Sunday, the holes in the Vikings' zone were larger than the one that caused the Metrodome roof to collapse a year ago.

"There should not be that type of gap," Frazier said. "We've been playing that coverage forever. And to see it played the way it was played today was just bad."

Frazier said this with a perplexed tone and that look of exhaustion. So often when he and the Vikings board the roller coaster this season, they wind up having little control of the ride.

Dan Wiederer • dan.wiederer@startribune.com