LOUDON, N.H. — NASCAR championship contender Mark Martin will drive for Hendrick Motorsports through 2011, an easy commitment for a driver at the top of his game.

Martin starts the Chase for the championship Sunday at New Hampshire International Raceway as the Sprint Cup Series points leader, a spot he earned through four victories this season.

"That shouldn't come as any big surprise," Martin said Friday of the contract extension. "Who would want to quit?"

Martin, in his 27th season of NASCAR, has repeatedly staved off retirement over the last several years. He ran a partial schedule in 2007 and 2008 and the time off re-energized him. Then came an offer to drive for elite Hendrick Motorsports, and Martin has thrived.

At 50, he's the elder statesmen of the 12-driver Chase field. But his high performance has made him a favorite for his first Cup title.

"As long as I can have fun, compete at a high level and have the opportunity to win, I'm going to continue to do this," Martin said. "I'm having a blast, and that's always been most important to me and my family."

Martin initially agreed to just one full season in the No. 5 car for Rick Hendrick, with an option to run at least a partial schedule in 2010. But he signed on for all of next year after a win in April at Phoenix — Martin's first victory since 2005.

He's also earned wins at Darlington, Michigan and Chicago, and the four wins this year equal the number of titles he won from 2000 to 2008. He's also won six poles.

Although he admits that 2011 is a long-term commitment, Martin said the sponsorship opportunity for HMS made the decision easy. GoDaddy.com will be the primary sponsor of the No. 5 for 20 races a season beginning next year.

"Rick, he had to make some decisions about some long-range things, and he really wanted it," Martin said. "With the success we were having, I don't see me falling off a cliff anytime soon. I hope that I'll be able to do the job. I understand that it works better for sponsor commitments and those types of things.

"So I am pretty comfortable. There is no place I'd rather be today than at the race track, and I didn't always feel that way, so I did something about it."

Greg Biffle, a teammate when Martin drove for Roush Fenway Racing, said the contract extension is not surprising.

"He's in damn good equipment and it will be hard to hang your hat up, driving and winning races and performing at the level that he is," Biffle said. "So I certainly wouldn't be a betting man on when he is going to hang his helmet up."