Steve Sheppard/AP

Tony Stewart (14) and Jimmie Johnson finished 1-2 in Sprint Cup action Sunday at Martinsville Speedway.

FORT WORTH, Texas -- Jimmie Johnson is probably at the end of the line on his Sprint Cup championship streak.

But it's not making him want to end anybody else's chances.

The five-time defending champion chose not to "bump and run" against Tony Stewart in a restart with two laps to go at Martinsville last weekend. He could have moved Stewart out of the way, clearing a lane for himself or teammate Jeff Gordon right behind him.

It's racing, and it would have been accepted. But Johnson told himself no. He respected Stewart's drive for the prize Johnson himself has won the past five years -- the NASCAR Sprint Cup title.

"I changed my mind," Johnson said. "With where he is in the points, what's going on, the fact that we raced throughout the day, he never touched me. ... I couldn't bring myself to that. He got by. I tried to be smart. That's typically how I race guys. I don't run over people to get positions."

It's tough to argue with Johnson's philosophy. It got him five championships.

But right now he's in sixth, looking up at what looks like a two-car battle between the driver he spared, Stewart, and the leader, Carl Edwards.

It's an eight-point difference between Edwards and Stewart as they come to Texas Motor Speedway for Sunday's AAA Texas 500. It's the second of TMS' two yearly Sprint Cup races, and the third-to-last stop in the 10-race "playoffs."

Three of the six fall winners in Fort Worth have entered the race No. 2 in the Chase standings, and two of those drivers (Edwards in '05 and Denny Hamlin last year) left Texas as the new Chase leader.

In an age when NASCAR has given its "have at it, boys" blessing to aggressive driving, it didn't escape Stewart that he could have been wrecked at Martinsville.

"Could Jimmie have just hauled it off in the corner, blown the corner to try to take us down? Absolutely," Stewart said. "He could have done that to anybody. He didn't do that to us. I think he knows we respect him and have that level of respect."

Nothing is promised for TMS, and Stewart will have to try to beat the winningest driver at TMS. Edwards has won three Cup races in Fort Worth, more than any other driver.

He's won six times on the Chase's closing three tracks, TMS, Phoenix and Homestead-Miami.

"We've had one of those up-and-down years, and we're having a run in this Chase now where we're hungry," Stewart said. "We're hungry for this. I feel like our mindset into these next three weeks, we've been nice all year to a lot of guys, given guys a lot of breaks. We're cashing tickets in these next three weeks."