DAYTONA BEACH, Fla. – It took about 10 minutes to wreck several cars at Daytona International Speedway on Friday.

Matt Kenseth triggered a five-car accident in the opening practice for the Sprint Unlimited, the nonpoints race that kicks off the season.

Kurt Busch, Carl Edwards, Mark Martin and Juan Pablo Montoya also were involved in the crash.

Busch’s No. 78 Chevrolet sustained the most damage, forcing the team to switch to a backup car for tonight’s exhibition event. Edwards and Martin also went to backups.

“It’s tough,” Busch said. “A lot of hard work goes into these cars, and six weeks of preparation can be trashed in six laps.”

Kenseth took blame for the melee, saying he didn’t see Busch gaining ground inside his No. 20 Toyota on the 2 1/2 -mile superspeedway.

“That was 100 percent driver error, my driver error,” Kenseth said. “I had no idea anybody was there and he had a run at the same time and I came down in front of him and he couldn’t get slowed up from staying out of me. It was a hundred percent my fault.”

The accident came less than 10 laps into the first practice of Speedweeks. It was supposed to be a learning session for NASCAR’s redesigned race car, the one dubbed “Generation 6,” and a preview of next weekend’s Daytona 500.

The season-opening event is a 75-lap made-for-TV event that includes five former Cup champions in the 19-car field.

Five-time series champion Jimmie Johnson, four-time champion Jeff Gordon and three-time champion Tony Stewart are in the field. So are two-time race winner Kevin Harvick and fan favorite Dale Earnhardt Jr.

Reigning Sprint Cup champion Brad Keselowski, though, didn’t earn a spot.

“I think any driver that’s not in a race is disappointed to not be in it,” Keselowski said.