HAVEN, WIS. - Matt Kuchar, like many men of a certain age, does not require a fountain of youth. All he needs is a baseball cap.

With his cap on, Kuchar's baby face and lanky frame evoke memories of 1998, when he was an amateur thrilling galleries at Augusta and Olympic Hills, while his father, caddying for him, annoyed competitors with his cheerleading.

When Kuchar removed his cap at the end of his second round at the PGA Championship on Friday, his expanded forehead and encroaching gray made him look more like what he is today: a 32-year-old man with a wife, two kids and a career that has caused him more stress than he would have guessed back in '98, when every golf course looked like a combination playground and ATM.

Four years after an unexpected detour to the Nationwide Tour, Kuchar seized the lead at the 2010 PGA, shooting a second-round 69 to take a one-shot lead at minus-8 on a blustery day at Whistling Straits.

This brawny course on the banks of Lake Michigan has given the world's best golfers a taste of the Midwestern lifestyle. Whistling Straits has welcomed them with swarms of bugs, high humidity, fog, rain, gusting winds and a layout that would seem to favor long hitters. Or billy goats.

With more than 1,000 bunkers and several holes that seem to hover over the lakeshore, the course is beautiful yet intimidating, but the straight-hitting, smooth-putting Kuchar has played it like it's a muni. "Not too much trouble to report in two rounds," he said.

Kuchar made four birdies and only one bogey, mirroring a season in which he ranks No. 1 on the PGA Tour in overall stats and in scoring average. He might look and sound like a longshot, but a new stretching program designed to increase his flexibility, and his affable perseverance, have made him one of the most consistent and likeable players on tour.

"I remember talking to some guys when I was fresh on the tour, talking to them about a 10-year learning curve out here," Kuchar said. "It didn't make much sense. I went out and had a win straightaway in 2002, and I thought it would be smooth sailing, and yet here I am 10 years into it and I feel like just now, maybe there is something to this 10-year learning curve."

Kuchar starred at Georgia Tech in the late '90s along with Bryce Molder, who shot a best-of-the-day 67 to move to 5 under. The two played practice rounds at Whistling Straits on Tuesday and Wednesday, giving Molder a sense of foreshadowing.

"I am never surprised by anything Matt does, but I played with him on Tuesday for 18 holes, and nine holes Wednesday," Molder said. "He had 13 birdies. Let's just say I didn't."

Lance Bennett, Kuchar's caddie, said Kuchar made five birdies in nine holes Wednesday. "This course really seems to suit him," Bennett said. "He's playing with a lot of confidence."

His face hasn't changed since he became a crowd favorite at the Masters in '98. He won the 1997 U.S. Amateur, succeeding a previous winner named Tiger Woods, and qualified for the '98 Masters and U.S. Open. He finished 21st at the former and 14th at the latter, making him the low amateur at both. Those rosy cheeks and that skinny torso made him look like a kid who had just sneaked onto the course on a bet.

He and Molder, though, found it difficult to translate college stardom into tour success.

"I think there's certainly a maturing process," Kuchar said. "I would have told you hands down, Bryce would have dominated out here straightaway. I thought Bryce had no chinks in his armor. I thought out of school, he was the best player in college golf. I thought there was a guy that's going straight to the big leagues and going to do well out here.

"It's just a funny game."

The wet conditions have made scoring possible for straight hitters, and implausible for anyone venturing into the fescue and sand.

Kuchar has hit 23 of 28 fairways and required only 52 putts, and is 4 under on par-5s because of his newfound length and accurate wedges.

These days, though, he's not pumping his fist and hearing his father yell. He's lost a little hair and learned a few lessons that could prove useful as he protects the lead at a major on the weekend.

"It's going by so fast," Kuchar said. "I still find myself feeling almost like a rookie. I still feel like I'm the kid from '97 winning the U.S. Amateur and playing in the Masters in '98. I still feel like I'm that same kid.

"It feels like that is just a blink of an eye ago. It's hard to believe that I have a wife and two kids and a whole different life and perspective now. But I still feel like a very, very young 32."

Two great rounds of golf and one baseball cap will do that for a guy.

Jim Souhan can be heard at 10-noon Sunday on AM-1500. His Twitter name is SouhanStrib. • jsouhan@startribune.com