The 51-year-old NASCAR Sprint Cup driver beamed when he slid behind the wheel of the No. 5 Chevrolet fielded by Hendrick Motorsports. Martin knew how hard crew chief Alan Gustafson and his troops had worked building cars during the offseason, so when he strapped into it last weekend for a qualifying run for the Daytona 500, a knowing smile came over his face.

“When we hit the racetrack, I knew we had picked up where we left off,’’ Martin said. “It was just fun. We were fast. We just had a blast. So I knew then that it was going to be an extension of last year.’’

That was evident when Martin became the oldest driver to win the pole position for the Daytona 500, doing so with a fast lap of 47.074 seconds (191.188 miles per hour) around Daytona’s high-banked, 2 1/2-mile tri-oval. Martin knocked teammate Dale Earnhardt Jr. from the top of the speed chart to give Hendrick a front-row sweep.

“It’s just incredible to be behind the wheel of that 5 car,’’ said Martin, who seemed rejuvenated last season, winning five races and finishing runner-up in the series in his return to a full-time schedule after running a part-time schedule the previous two seasons.

For Martin, though, his pole victory for Sunday’s race was a first. Last year, Martin earned the first front-row start of his career at Daytona when he qualified second-fastest behind Martin Truex Jr. Now, in his 26th start in the Daytona 500, Martin will be treated to the best seat in the house.

Gustafson, who grew up watching Martin race at Daytona, said it was “really cool’’ to be able to help Martin achieve another milestone.

“Mark has enough records to have his own record book,’’ Gustafson said. “When you can get a new one with him - and we’ve done it a few times in this car, done something he’s never done in his career, be on the pole for the Daytona 500, something he’s never done - then I’m really proud to be able to do something he’s never done, because he’s done an awful lot.’’

For all he has accomplished, though, Martin said he could have never imagined becoming a championship contender this late in life had he not stopped to take stock of his career and life.

“I wouldn’t have taken this opportunity [at Hendrick] without having taken a couple of years off, charging my batteries, reassessing my life and everything that went on during that time,’’ Martin said. “What does register is I had the most fun of my life last year, and I’m going to have a blast this year. I think that’s really exciting.

“Not many people my age can say this is the best it’s ever been and, for me, it is.’’

The reason Martin feels that way is because of his partnership with Gustafson, whom Martin credited for helping him rediscover the fun in racing. So how does he intend to duplicate that feat this season?

“Well, 2010 will be a challenge to have as much fun as we had in 2009, because part of the time, I don’t know about Alan, but for me, I was surprising myself,’’ Martin said. “It was a surprise. And so we have higher expectations, or at least I do, you know, this year.’’

Joining the Hendrick organization drastically altered Martin’s expectations. Before that, though, he seemed resigned to semi-retirement.

“I had conceded myself and my career to what I was doing,’’ Martin said. “I was very fortunate to drive the 01 [for Ginn Racing] and nearly win the Daytona 500 [in 2007 when he was nosed out at the finish by Kevin Harvick] and to drive the 8 car [for Dale Earnhardt Inc.], it was a fast racecar, had a lot of fun, so I did it on my terms, and I wasn’t really at the time missing anything.’’

Except, that is, a chance to win a championship and, possibly, the Daytona 500.

Those were the only glaring holes on Martin’s glittering résumé.

“But when I was presented with the opportunity to drive the 5 car, I knew more than anything else, I knew that I would regret for the rest of my life not taking the opportunity,’’ Martin said. “And, boy, was I right about that.

“It looks like I’ve done so many things right, but really, I’ve just been lucky and stumbled around. I’ve just stumbled around, fell into this 5 car, and it’s the best thing that ever happened to me.

“I’m so happy to be at the racetrack. There’s no place in the world that I’d rather be.’’

Michael Vega can be reached at vega@globe.com.