Dunlap will bid to become the first amateur to win on the tour since Phil Mickelson 33 years ago when he takes a three-shot lead into the final round of The American Express tournament in California on Sunday (Monday AEDT).
The reigning US Amateur champion, American Dunlap proved steely as he posted a stunning 12-under 60 on Saturday, playing each nine of the La Quinta course - one of three courses in the tournament rotation - in just 30 strokes as he amassed 10 birdies and an eagle to get to 27 under.
He became only the second amateur to shoot 60 on the tour and, if he wins, he stands to gain all the benefits that go with it, including a tour card and two-year exemption - except the $US1.51 million ($2.3m) winner's cheque.
"The putter felt so good," Dunlap said. "The hole looked like a funnel."
Dunlap leads from Sam Burns who shot a steady 65 on the Stadium Course to stay in contention after taking the lead with his career-low 61 on Friday.
Justin Thomas shot 61 on the Stadium Course and was four shots back of Dunlap.
Endycott posted his 62 on the Nicklaus Tournament Course, with eight birdies and an eagle as he rocketed up 66 places on the leaderboard.
He was tied 23rd at 16 under, one shot ahead of fellow Australian Min Woo Lee, who lost ground with a 70 at La Quinta, while countryman Jason Day was a further shot back after a 68 at the Stadium Course.
The final round will be played on the Stadium Course, where Thomas tied the course record on Saturday.
Dunlap is bidding to become the second-youngest winner on the tour since 1931. Jordan Spieth was 19 when he won the John Deere Classic in 2013.
"I think it's going to be hard either way," Dunlap said.
"Looking at this place, like, it's supposed to be easy, and guys are shooting low numbers, but you still have to go do it. It's still a golf course, and you still have to hit good shots.
"There's out of bounds everywhere. For (Sunday), there's a lot of water out there. Just hit one good shot at a time, and try to stack 'em and give myself a lot of good looks."
Two-time major champion Thomas is winless since his second PGA Championship victory in May 2022 but will have a chance to catch his fellow Alabama product.
"Didn't think I was going to have to deal with a freakin' college kid shooting 60 today," Thomas said with a grin.
"He's a stud. He's the real deal. I think how well he's handled the big moments, it says a lot about somebody.
"It seems like the bigger the stage, the better he plays. I've never played with him before. I probably would have preferred our first time in a practice round."
Dunlap joined Tiger Woods last year as the only winners of both the US Amateur and the US Junior Amateur. He played in the past two US Opens due to his amateur success, but The American Express is just his fourth PGA Tour event.
with The AP
