DAYTONA BEACH, Fla. — The rain was coming, and Matt Kenseth knew it was time to get going.

It was the Daytona 500, a race where drivers wait until the very end to make their big move for NASCAR’s biggest prize.

Only this time, nobody knew when the end would be.

The rain that had threatened Sunday’s season-opening race all day finally rolled in moments after Kenseth slid past Elliott Sadler for the lead, and the former NASCAR champion was forced to sit out a 20-minute delay before claiming victory. It was just the fourth rain-shortened 500 in the race’s 51-year history, and first since Michael Waltrip’s 2003 victory.

“It’s going to be really wet out here, because I’m crying like a baby,” the usually cool Kenseth said as he choked back tears.

Coming off one of the worst seasons of his career, Kenseth’s 2009 start seemed to be headed in the wrong direction. He wrecked his primary car, had to go to a backup and started at the back Sunday.

Had rain not been forecast, he might still have been running at the back of the field with 54 laps to go, because that’s where veterans usually wait out the dicey Daytona racing before making a late charge.

But the weather radar showed the rain was coming, and crew chiefs up and down pit road urged their drivers to go for it.

Kenseth sliced his way through the field, then used a huge push from Kevin Harvick to take the lead from Sadler. A caution came out moments later for a spin by Aric Almirola, and the sky opened up about the same time.

After two laps under caution, NASCAR stopped the race and brought the drivers to pit road. Most climbed from their cars to await NASCAR’s decision.

Kenseth did not, choosing instead to sit silently inside his Ford away from his nervous supporters. He began to cry when NASCAR gave him the victory, his first in the Daytona 500 and first since the 2007 season finale.

It was also the first Daytona 500 win for team owner Jack Roush.

“I tell you what, after last year, winning a race means a lot to me,” Kenseth said. “I’ve had a lot of great opportunities in my life — from my family getting me in racing and really … all the sponsors that we have that have stuck by us and made this happen in an up-and-down economy.

“Man, I don’t know. Winning the Daytona 500 is definitely a dream moment. It’s just an unbelievable feeling.”

Harvick, who used a push from Kenseth to win the 500 in 2007, finished second and said Kenseth would be a popular winner among his competitors.

“I think Matt’s obviously a pretty stand-up person and a great race car driver,” Harvick said. “I think he’s one of those guys that he can win seven or eight races in a year and never receive any credit. He’s a really good race car driver. He’s a champion, Daytona 500 champion.”

AJ Allmendinger, who had to race his way into the field in one of Thursday’s qualifiers, finished third.

Clint Bowyer was fourth and Sadler was fifth, devastated he lost the lead moments before the rain stopped the race. He led 24 laps and was out front during an earlier caution, hoping the sky would open up at that moment to give him the win.

“That’s just my luck,” he radioed his crew. “It’s raining on the radar and not on the track. Welcome to the team.”

Sadler nearly lost his job in December, when team management decided to replace him with Allmendinger. He filed an injunction to stop the move, and the team changed its mind after merging with Petty Enterprises in early January.

A chance to win the 500 would have been sweet redemption for Sadler, who instead was left wondering what he did wrong.

“If I would have made a better and smarter move, I’d be in Victory Lane right now,” he said. “I put my heart and soul to come in here to Daytona, Speedweeks, try to compete at the top of my game, ’cause I knew I had a lot of eyes on me to run good.

“It would have been cool to finish like that, but just wasn’t meant to be. Very hard to swallow. Very emotional.”