Jimmie Johnson celebrates wining the NASCAR Sprint Cup Series Tums QuikPak 500. Johnson won the race Sunday at the Martinsville Speedway in Martinsville, Va.

Martinsville, Va. ? Jimmie Johnson is on a roll again, and whether he’s willing to admit it or not, while everyone else in NASCAR is chasing him, he’s chasing history.

Johnson led 339 laps Sunday as he and his Hendrick Motorsports teammates again dominated at Martinsville Speedway, and the two-time defending Sprint Cup champion padded his lead in his bid for a record-tying third championship in a row with four races remaining.

Only Cale Yarborough, from 1976-78, has won three straight championships in stock car racing’s premier series, and Johnson is looking more and more as if he’ll be the second.

“I’m going to have to answer those questions one of these days, aren’t I?” Johnson said of the ones about Yarborough and taking a position beside him in history.

Johnson’s sixth victory of the year extended his points lead from 69 to 149, and while his closest challengers vowed that the Chase race isn’t over, the plaudits keep coming, too.

“There’s a lot of great teams that were huge in the sport,” Dale Earnhardt Jr. said, lumping Johnson and crew chief Chad Knaus in with his father and Richard Petty, both seven-time champions, and Hall of Famers David Pearson, Yarborough and Junior Johnson.

“To pack it in three years and just dominate like that, there’s only a half a dozen teams that have ever done anything like that, been that strong consistently,” Earnhardt said.

And it could only be the beginning of another big finish for Johnson.

It was a year ago that this race started a four-race winning streak for Johnson, a run that he said left him leaving Phoenix thinking, “I cannot believe I’m experiencing this.”

Now, to experience it again, he’s not planning on letting up at all.

“As long as I can stay scared and on my heels and worried about losing this thing, the better this team’s going to be. If we start getting comfortable and complacent, we’re going to stub our toes, make mistakes,” he said. “We’re trying to keep our eye on the prize.”

So are the rest of the contenders, even if it’s getting farther and farther away.

“We’re going to come and get them,” said Greg Biffle, who climbed to second in points. “We’ve got four more chances, and we’re going to some of our best places, so they better be on their ‘A’ game.”