Jamie McMurray scored a surprise win in Sunday’s Daytona 500, following two long delays because of a crumbling track and a series of late-race accidents.

McMurray was in sixth place for two of the last three restarts but was second for the final restart and, helped by Greg Biffle pushing him, was able to pass Kevin Harvick and come through to score the biggest win of his career. He led only the race’s last two laps – the fewest of any Daytona 500 victor.

McMurray, 33, lost his ride with Roush-Fenway Racing last year but was picked up by Earnhardt-Ganassi Racing, where he replaced Martin Truex Jr as Juan Pablo Montoya’s team-mate. McMurray showed his potential by finishing second to Harvick in the previous weekend’s Budweiser Shootout before stealing victory in the 500.

“It’s unbelievable,” a tearful McMurray said. “I can’t express what it means. I’m so thankful to Chip and Felix and Bass Pro Shops for taking a chance on me and letting me come back. It’s a dream, it really is. I spun the tyres on the restart but Greg helped me out a lot. It’s just a gamble which line you choose to get the biggest run and Greg gave me an unbelievable push down the backstretch. Then I saw the #88 car [Dale Earnhardt Jr] behind me and I thought, ‘Oh no!’ because he had a good car and the Earnhardts have won a lot of races at Daytona.”

Earnhardt Jr came rocketing through from 10th on the final restart to finish a rousing second. It was his best result since winning at Michigan in 2008. “If there was enough room for the radiator to fit, you just held the gas down and prayed for the best,” he said. “It was a lot of fun. We all wiggled through there but Jamie got away from us. It was frustrating to come that close.”

Biffle looked a likely winner in the closing stages but fell to third. He ran among the leaders most of the way and led 27 laps. “I feel good about helping Jamie get clear and get out front,” he said of the final restart. “I just wish I could have waited until the backstretch to make my run on him. I had a huge run going and I just couldn’t clear him. I tried on the frontstretch and gave Junior and all the guys an opportunity to get back up beside us. I just made my move too soon.”

Another favourite to win was Harvick, who led more laps (41) than anyone else and seized the lead on the penultimate restart before fading to seventh. “It was wild,” he said. “The #99 car [Carl Edwards] went to the middle and jammed it all up. He didn’t really know where he was going. I just wish we had somebody behind us who knew how to draft.”

The race was delayed for more than two hours by a hole in the track in turn two that took shape midway through the race. The first delay occurred about two-thirds of the way into the 500 while the track’s maintenance staff tried to repair the damage. The race eventually took a total of seven hours to run and many fans left during the repairs, so it was a difficult start to the NASCAR season.