RICHMOND, Va. — This was supposed to be Kyle Busch's runaway championship. Then Carl Edwards turned up the heat.

Not to be overlooked, though, is Jimmie Johnson. He's thrown his experience and some momentum into the fray, and is now a legitimate threat to win his third consecutive title.

The two-time defending NASCAR champion held off winless Tony Stewart on Sunday at Richmond International Raceway to grab his second consecutive win, fourth overall this season, and take a big boost into the Chase for the championship.

Johnson is trying to become the first driver to win three straight titles since Cale Yarborough (1976-78), but doesn't want to focus on the historical possibilties in front of him.

"I do think about it," admitted Johnson, "but the less I think about it, the better I'm going to be. The less I can think about all this stuff the last 10 races, the better I am going to be. I just need to fall back to the confidence I have in my race team and my abilities.

"If you show up and you're swinging for the fences every time, you're going to make mistakes."

Johnson hasn't of late, chasing down Busch and Edwards to arguably claim the role of championship favorite.

Busch, winner of eight Cup races this season, is the top seed in the Chase. Edwards is second based on his six victories and Johnson is third. They are the only three drivers in the field with multiple wins, and five of the contenders start the Chase winless on the season.

Edwards, however, believes all 12 drivers will have a shot at the title when the 10-race Chase begins next Sunday in New Hampshire.

"Anything can happen," he said. "I think it's going to be defined by your bad days."

And there were plenty of them on Sunday: Busch was wrecked twice — once by Dale Earnhardt Jr. while leading — and David Ragan had numerous on-track miscues to eliminate himself from Chase contention in a race delayed a day by NASCAR because of Tropical Storm Hanna.

Ragan and Kasey Kahne were the only two drivers mathematically eligible to race their way into the Chase field. Ragan put on a gutsy push before contact with other cars ended his run with a 32nd-place finish.

"Regardless of how we ended today, I told everyone before the race whether we made the Chase or not, it wasn't going to be solely on the Richmond race," Ragan said. "I can look back at three or four races earlier in the year where we didn't do a good job and resulted in the loss of a few points."

Kahne finished 19th, giving the final Chase spot to Clint Bowyer.

"I drove everything I could all day," Kahne said. "It was a long day in the pits — we came out close to last almost every time."