It is a debate that has polarized American football fans for over two years. Is former college favorite Tim Tebow an NFL caliber quarterback or not?

After Tebow's first start of the season on Sunday, the debate remains open for all but the most fanatical in either camp.

The Floridian combines a Johnny Unitas throwback hairstyle with a running back's physique, a winning smile and a take-home-to-Mom politeness, all wrapped up with home-schooled Christian values.

That makes him a marketing and branding dream for the Denver Broncos, the NFL, television and all manner of sponsors.

But there are those who think he might prove to be the NFL's version of Russian tennis player Anna Kournikova -- popular, attractive and talented but not cut out for the weekly grind of the professional circuit.

For three quarters of the game at the Miami Dolphins, the critics appeared right. Tebow's passing was poor, he needed too much time to read situations and he just never looked comfortable.

Then, with time running out, he took the game by the scruff of the neck and the Tebow that had delighted fans of the 2008 Florida Gators national championship winning team -- brimming with confidence and willing to improvise -- re-emerged and won the game for his team.

The passing yardage numbers only tell part of the story. In terms of his impact on the game, he simply went from zero to hero.

Two touchdown passes and a successful two-point conversion that he ran in himself, took the Broncos from 15-0 down to overtime, which they won with a field goal.

It was a Hollywood storyline and proof, if nothing else, of Tebow's remarkable character and confidence.

But did it show he is good enough to become a week-in-week-out, four quarters, every down, quarterback?

"He's got those intangibles that we see every time he plays," former Broncos Hall of Fame quarterback John Elway, now executive vice-president, told the Denver Post.

"When that clock is sticking down and something's got to happen, that's what triggers the competitor in him.

"He's a guy that as long as there's time on the clock, he's going to give us a chance to win. Those are things you can't coach," he said.

RANGE OF WEAPONS

Coaching work is evident in Tebow's game though -- his throwing action has been adjusted since his college day, even if it is yet to reach the smoothness of delivery and the premium accuracy that is required in the pro game.

His reading of blitzes was poor -- he was sacked seven times by the Dolphins -- and he looked slow at times 'reading' situations.

In Tebow's defense, his coaches took a conservative approach to play selection until late in the game. He also lacks a great range of weapons in the Broncos' receiving corps.

It will take much more than one game for a definitive verdict on Tebow to be reached.

"We said all along, you know, Tim is a work in progress," Broncos head coach John Fox told reporters on Monday as he looked back on the comeback victory.

"It was only his fourth start in the National Football League and he will just continue to get better. I think he'll tell you and I know I'd tell you, I liked the last five minutes better than the first 55. We feel like he'll improve."

Perhaps the Broncos will need to draw some conclusions from the way Tebow delivered so well in the latter stages. Perhaps they will need to go back to what made their quarterback so effective in college football.

"They are going to have to run the spread offense with this guy and run the running game out of the spread," ESPN football analyst Herm Edwards told the New York Times.

"If you want to win some games, let him play that way. If you put him in a conventional offense, he's going to struggle."

The debate may not be about whether Tebow can make it in the NFL. It may be a case of whether the NFL can make it for Tebow.

Does the professional league have enough room, enough coaching freedom and strategic flexibility to find a way to let Tebow be Tebow?