Fred Couples is 52, and there’s no telling the relative age of his vertebrae. Yet as he walks on the grounds of Augusta National Golf Club, his back loosens up, and the years melt away. As the sun cast his shadow across the 18th green Friday, the applause came as it has for nearly three decades. He played his first Masters in 1983, when Jason Dufner was 6, when Sergio Garcia was 3, long before Rory McIlroy was born. His hair is gray. His game, here, still produces brilliant colors.

“I feel like I’m very young when I get here,” Couples said.

It is, then, the only way to explain what transpired Friday, in a chilly and breezy second round of the Masters, in which Couples somehow holds a share of the lead. That Dufner, an Alabaman of few notable accomplishments, shot 70 to get to 5-under-par 139 wasn’t terribly shocking, because he contended last summer at the PGA Championship, which he lost in a playoff. That McIlroy, the U.S. Open champ from Northern Ireland and one of the game’s preeminent stars, managed a 69 to get to 4 under was all but expected, because McIlroy could eventually be tailored for one, two, three — pick a number of green jackets.

Lee Westwood? Even with a stumble into a double bogey at 18, there’s no reason the Englishman ranked third in the world shouldn’t contend here; his 73 left him at 4 under. Sergio Garcia? The Spaniard may have, previously, expressed some disdain for this hallowed event, but he has long had the ability to shoot 68, as he did Friday, and climb into that tie for third at 4 under. South African Louis Oosthuizen and American Bubba Watson: different backgrounds, different characters, different games, the same ability to contend here, with a 72 and a 71, respectively, both in that pileup at 4 under.

Even Phil Mickelson, who owns three green jackets, expected himself to make a move after a bizarre opening round. And when he rolled in a birdie putt at 18, there he was, with a 68 that took him from the outside edge of the picture to the inside edge, 2 under.

All enough to turn a graybeard’s beard gray.

“I know Phil just birdied 18 for 4 under, and Sergio is behind me, and Rory was a little bit behind me, and Lee was ahead of me, and there was a lot going on there,” Couples said. “And for me to be part of it, it’s really amazing.”

To be clear, he is more than just a part of it. The 1992 Masters champ opened with 72 and was even par through six holes Friday. He then rolled in a 20-footer at the seventh for one birdie, knocked a wedge to three feet at the par-5 eighth for another, and rolled in a 35-footer for one more at the maddening ninth. Westwood was leading at the time, and McIlroy was moving, too, but it was Couples’s move — finished with birdies at 15 and 16 — that warmed the chill and shook the old pines, a 67.

Part of the gallery’s reaction to Couples is his history here, not only the win in 1992, but 10 other top-10 finishes. Two years ago, he opened with 66 and finished sixth. Last year, he was the same 5-under 139 at the midway point, though he trailed McIlroy; he eventually tied for 15th.

But the other part of the warm applause is his attitude. Couples’s next violent lash at the ball will be his first. His overcooked-noodle of a swing is as relaxed now as it ever was, right in line with his demeanor.

“He’s just cool,” McIlroy said. “I hope I’m that cool when I’m 52.”

Couples’s attitude, then, will fit right in with that of Dufner, the 35-year-old whose pre-shot waggle at the ball is about as much of a show as he allows on the course. He bogeyed 18 to, at the time, drop out of a tie with Westwood for the lead. His reaction: flat-line.

“There’s a lot more going on out there than appears,” Dufner said. “I feel like I have the same emotions and same thought processes as a lot of guys, but I seem to not show it quite as well as some other players. It’s just difficult. It’s a test of yourself.”

Now, the test truly begins. “Tomorrow,” said a reinvigorated Mickelson, “will be a critical day.”

It is true for Westwood, the 38-year-old who is seeking his first major and must overcome his closing, three-putt double bogey. It is true for McIlroy, who made a wonderful par save at 18 to hold his spot. It is true for Garcia, who put himself in position in the third round a year ago — then shot 42 over the back nine. It is true for any of the 30 players within five shots of the lead.

“There’s a lot of time left,” Mickelson said, “and there’s a lot of birdies out there.”

How many remain for Couples?

“I’m certainly not Rory McIlroy or Phil Mickelson,” he said. “But I do know this course pretty well. I’ve had a lot of success here.”

As Couples spoke, a face appeared in the small, square window of a door behind him. It was McIlroy. Playfully, the 22-year-old knocked on the glass. Hurry up, old man.

Couples, though, was content to sit, chat — and dream.

“Can I win?” Couples said. “I believe I can. Yes.”