A terrifying crash that hospitalised a leading driver has cast a pall over the Daytona 500 Nascar event in Florida.

Denny Hamlin won his second straight Daytona 500 and third overall, but that was of secondary importance, as grave concern was initially held for the welfare of Ryan Newman.

Newman’s team have since advised media that his injuries are serious but not life-threatening.

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Newman had surged into the lead on the final lap when Ryan Blaney’s bumper caught the back of his Ford and sent Newman careering into the perimeter wall.

Newman’s car flipped, rolled, was hit on the driver’s side by another car, and finally skidded across the finish line engulfed in flames.

It took several minutes for his car to be rolled back onto its wheels. He was placed in a waiting ambulance and taken directly to a hospital.

Drivers were stricken with concern, including a rattled Corey LaJoie, the driver who hit Newman’s car as it was flipping.

“Dang I hope Newman is ok,” he posted on Twitter. “That is worst case scenario and I had nowhere to go but (into) smoke.”

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Hamlin is the first driver since Sterling Marlin in 1995 to win consecutive Daytona 500s, but his celebration in victory lane was subdued.

“I think we take for granted sometimes how safe the cars are and number one, we are praying for Ryan,” Hamlin said.

Runner-up Blaney said the way the final lap shook out, with Newman surging ahead of Hamlin, that Blaney locked in behind Newman in a move of brand alliance for Ford.

“We pushed Newman there to the lead and then we got a push from the 11 … I was committed to just pushing him to the win and having a Ford win it and got the bumpers hooked up wrong,” he said. “It looked bad.”

NASCAR gave no immediate announcement on Newman’s status and officials moved bystanders away from the crash scene.

Hamlin had eight Ford drivers lined up behind him as the leader on the second overtime shootout without a single fellow Toyota driver in the vicinity to help him.

It allowed Newman to get past him for the lead, but the bumping in the pack led to Newman’s hard turn right into the wall, followed by multiple rolls and a long skid across the finish line.

Hamlin’s third Daytona 500 win put him alongside six Hall of Fame drivers as winners of three or more Daytona 500s.

-with AAP