FONTANA, Calif. ? Somehow, Greg Biffle kept his car pointed in the right direction long enough to take the checkered flag.

“I lost all the rear grip there with three (laps) to go,” Biffle said as he celebrated his victory Sunday in the Auto Club 500. “I just barely touched the wall, skinned it, two or three times there at the end, and I was just able to keep it under me. We had the fastest car on the racetrack, but just not right there at the end.”

Biffle, who won the 2004 season finale in November, ran strong throughout the 250-lap race on California Speedway’s two-mile oval, taking the lead for good on lap 228 and building an advantage just big enough to hold off a last-ditch effort by runner-up Jimmie Johnson in the second NASCAR Nextel Cup race of the season.

“Man, I saw Biffle hitting the wall and sideways a few times there at the end, and I could hardly believe he got to the end,” said Johnson, who passed Kurt Busch for second and nearly caught Biffle on the final lap. “But he had a strong car, and he did a really good job.”

Biffle, who finally was able to figure out the right combination in the first test of NASCAR’s new aerodynamic rules, twice came back from as far down as 30th.

“I had to pass every car, and I earned it,” the winner said. “That’s why I freed the car up so much is because I was back in that traffic. Then, when I got back out front, it was so dang loose that I couldn’t drive it.”

Greg Biffle shows his trophy after the NASCAR Auto Club 500. Biffle won Sunday at California Speedway in Fontana, Calif.

Roush Racing had a great day, with Biffle winning his fourth Cup race, reigning series champion Busch finishing third and taking the season points lead, Carl Edwards taking fifth and Mark Martin seventh. Matt Kenseth also ran in the top 10 most of the day, but fell off the lead lap on lap 234 with a flat tire and wound up 26th.

Jamie McMurray finished fourth, followed by Edwards and Harvick.

This was the first race in which the Cup cars ran with shortened rear spoilers and softer tires.