Other than a couple of incidents at Talladega in 2005, where he was blamed for starting two big crashes, Jimmie Johnson's reputation as a gentleman driver has been pretty much untouchable.

He's certainly won his share of races — 25 of them — and most have come with a dominant car, finesse or strategy.

But finally winning a NASCAR Nextel Cup championship after coming close in three of his first five seasons in the premier stock car series apparently has given Johnson yet another gear he can reach for.

On Sunday, he overwhelmed the rest of the field in the first two-thirds of the Cup race at Atlanta Motor Speedway, several times building leads of more than 6 seconds — a quarter of the 1.5-mile oval. But several caution flags slowed the race, and Johnson found himself coming off pit road in third during the last set of stops by the leaders.

Ahead of him were two other former Cup champions, Matt Kenseth in second and Tony Stewart leading.

Kenseth kept getting super-fast pit stops from his No. 17 Roush Fenway Racing crew that put him out front for a while. But he couldn't stay there.

Stewart, on the other hand, looked just as strong as Johnson at times, particularly at the end of the race. He charged to the front of the field after a bad pit stop knocked him from fourth to 13th just before the halfway point in the 325-lap race, and wound up leading 121 laps to Johnson's 135.

The final restart came 11 laps from the end and it took Johnson just three trips around the oval to move past Kenseth into second.

Stewart, a two-time Cup champion, is one of those guys who represents the racing cliche: You can catch him, but passing him is another thing.

Johnson's No. 48 Hendrick Motorsports machine got to the back bumper of Stewart's No. 20 Joe Gibbs Racing entry on lap 320. He drew alongside Stewart twice on lap 321 before slipping back. Finally, on lap 322, Johnson made an inside move and shot past.

There's no give-up in Stewart, who may be the hardest racer in NASCAR since the late Dale Earnhardt. He drove to the outside, right along the wall and tried to squeeze back past Johnson, but the reigning champion shut the door, sliding just inches up the banking.

Stewart's car scraped the wall and he fell back, watching from second place as Johnson pulled away to win by half a straightaway.

"Jimmie has always had the talent, now he's got the confidence, too," said Chad Knaus, the crew chief who has been with Johnson since 2002, his first full season in Cup. "He's not afraid to stick his nose in there in a tough spot, especially if a win is on the line."

Stewart wasn't too thrilled with Johnson for pinching him into the wall. But Stewart appeared to be nowhere near as angry as he would have been if a lesser driver had cost him a win.

"He had a faster car and he's probably going to get around us anyway," Stewart said, shrugging. "But I'd like to have seen him give me room to race him for it."

Johnson began the season on a down note by crashing out in 39th at Daytona. That also ended his string of 104 consecutive races in the top 10 in the season points, dating to the fourth race of 2004.

But he came back to finish third the next week at California, won two weeks later at Las Vegas and, with his win in Atlanta, has now moved to fourth in the season points.

"Jimmie and I and the team were all very proud of that streak of being in the top 10 in points for so long," Knaus said. "Maybe this will get us started on another long streak."