FONTANA, Calif. – Jimmie Johnson had enough time to think about how good his car was — and worry that he might blow it.

“I’m just happy that we all did our parts tonight and didn’t let this great opportunity slip away,” the two-time reigning NASCAR Sprint Cup champion said after an overpowering victory Sunday night at Auto Club Speedway.

Johnson’s third victory of the season served notice that he is not to be taken lightly with the start of the Chase for the championship only two weeks away.

“It was an awesome race car all night long,” Johnson said after leading 228 of the 250 laps in the Pepsi 500. “We really didn’t touch much all night long and the car was fast and good. And the track just came to us.

“More than anything, I’m just happy to close the deal. It’s very, very rare to have a car that dominant and it’s easy to do something stupid to spoil that.”

Asked if he has had a car this superior before, Johnson said, “I think this is the most dominant car and victory we’ve had, but I can remember one other time, and I blew the opportunity. My rookie year at Lowe’s (Motor Speedway), I think we led 580 miles of that (600-mile) race and I slid through the pits and lost us the race.”

Runner-up Greg Biffle also had a fast car, but barely kept in touch with Johnson’s No. 48 Chevrolet on the 2-mile oval, finishing 2.076 seconds behind the winner.

“The 48 was phenomenal,” Biffle said. “We see that happen every once in a while a guy gets it set up right, gets the car running good.”

Johnson won the race at the former California Speedway for the second straight year and showed points leader Kyle Busch and Carl Edwards — the two hottest drivers in the series coming into this race — that he remains a serious contender for a third straight title.

“I hope so,” Johnson said. “I’m just not sure how it’s going to shake out. The weak spot for us has been the mile and a half and two-mile tracks and the Chase is loaded with those.

“We’ve been getting better each week. I’m happy to be on a big track and win on a big track. I really think we’re doing the right things to have a fighting chance at the championship and that’s all we can ask for.”

In February, Johnson led the most laps here but lost the race when Edwards passed him with 23 to go. This time, nobody could touch Johnson.

Time after time he built leads of between 5 and 12 seconds, only to see them erased by yellow flags. But it didn’t faze Johnson, who just rebuilt the margin after the next restart.

On a pit stop on lap 162, during a caution period, Johnson took four tires and found himself in sixth on the restart, trailing five drivers who had each taken two tires on the stop.

After the restart on lap 166, Johnson was fourth after one lap, second after two trips around the 2-mile oval and back in the lead on lap 168.

On the next pit stop, on lap 182 during another caution, Johnson’s jackman got tangled up in the air hose in a rare pit misstep by the team. Johnson again came out of the pits in sixth. And, again, he rocketed back into the lead in just three laps after the green flag waved.

“The car was really good, especially the first 15 or 20 laps,” Johnson said. “When you have a car like that, it doesn’t really matter where you are on the track.”

Biffle’s Roush Fenway Racing crew celebrated as if they had just won the race when he beat Johnson off the pit lane on their last stop on lap 219. But it took Johnson less than half a lap to regain the lead on the way to his 36th career win.

Biffle just shook his head when asked how good Johnson was.

“He would get better as the run went anyway. But he had more grip up off the corners,” Biffle said. “The 48 was a better car tonight. If it’s not 18 (Busch) beating us, it’s the 48.”

For a change, neither Edwards, who had won two straight races and three of the last four, nor Busch, with eight wins and runner-up the previous two weeks, were in contention.

Denny Hamlin finished third, followed by Kevin Harvick, Matt Kenseth, Edwards, Busch and Kasey Kahne.

Johnson, Hendrick Motorsports teammate Dale Earnhardt Jr., who finished 11th, and Jeff Burton, who was 17th, clinched spots in the 12-man Chase for the championship that will begin after next Saturday night’s race at Richmond. They joined Busch and Edwards who had previously locked up spots in the postseason.

Biffle, sixth in points, will make the Chase field simply by starting at Richmond, while seventh-place Harvick needs only to finish 42nd or better, while Tony Stewart, eighth after finishing 22nd Sunday, can lock up a spot by finishing 35th or better.

Drivers vying for the final positions in the Chase remained close, with Kenseth vaulting past 15th-place Jeff Gordon into ninth in points, and Hamlin and 10th-place Clint Bowyer 11th and 12th in the standings. David Ragan, who finished 13th Sunday, stayed in 13th, but is just 17 points behind Bowyer, while Kahne remained 14th, 44 points out of the Chase lineup.