(AP) -- Tony Stewart won a chaotic Nationwide Series race at Daytona International Speedway that ended with a frightening last-lap crash that appeared to injure fans when rookie Kyle Larson's car sailed into the fence that separates the track from the seats.
The front end of Larson's car was ripped away, and a gaping hole was cut in the fencing. Pieces of the car sailed into the grandstands and emergency workers could be seen attending to fans.
Ambulance sirens were heard behind the stands, which were briefly shrouded in smoke from Larson's burning engine, which appeared to be wedged into the fence.
A subdued Stewart did not celebrate in Victory Lane.
"The important thing is what going on on the front-stretch right now," the three-time NASCAR champion said. "We've always known, and since racing started, this is a dangerous sport. But it's hard. We assume that risk, but it's hard when the fans get caught up in it.
"So as much as we want to celebrate right now and as much as this is a big deal to us, I'm more worried about the drivers and the fans that are in the stands right now because that was ... I could see it all in my mirror, and it didn't look good from where I was at."
Regan Smith was leading coming to the checkered flag when he was turned sideways into the wall. Cars began wrecking all over the track, and Larson's car went sailing into the fence.
Stewart slid through the wreckage to the win.
When Larson's car came to a stop, it was missing its entire front end. The 20-year-old, who made his Daytona debut this week, said he first thought of the fans.
"I hope all the fans are OK and all the drivers are all right," Larson said. "I took a couple big hits there and saw my engine was gone. Just hope everybody's all right."
He said he was along for the ride in the last-lap accident.
"I was getting pushed from behind, I felt like, and by the time my spotter said lift or go low, it was too late," Larson said. "I was in the wreck and then felt like it was slowing down and I looked like I could see the ground. Had some flames come in the cockpit, but luckily I was all right and could get out of the car quick."
It appeared fans were lined right along the fence when Larson's car sailed up and into it.
Shortly before the final three-lap sprint to the finish, Michael Annett was taken to a hospital for further evaluation after a 13-car accident with five laps remaining.
NASCAR said Annett was awake and alert, but undergoing further tests. That accident stopped the race for a red-flag of nearly 20 minutes.
The last-lap accident began when Smith tried to block defending Sprint Cup Series champion Brad Keselowski to preserve the win.
"I tried to throw a block, it's Daytona, you want to go for the win here," Smith said. "I don't know how you can play it any different other than concede second place, and I wasn't willing to do that today. Our job is to put them in position to win, and it was, and it didn't work out."
Keselowski watched a replay of the final accident, but said his first thoughts were with the fans. As for the accident, he agreed he tried to make a winning move and Smith tried to block.
"He felt like that's what he had to do, and that's his right. The chaos comes with it," Keselowski said. "I made the move and he blocked it, and the two of us got together and started the chain events that caused that wreck. First and foremost, just want to make sure everyone in the stands is OK and we're thinking about them."
Keselowski said the incident could cast a pall on Sunday's season-opening Daytona 500.
"I think until we know exactly the statuses of everyone involved, it's hard to lock yourself into the 500," Keselowski said. "Hopefully we'll know soon and hopefully everyone's OK. And if that's the case, we'll staring focusing on Sunday."