America's Matthew Wolff has an historic victory in his sights after a stunning performance on his US Open debut at Winged Foot.
Wolff began the day four shots off the lead but compiled a brilliant third-round 65 to finish five under par and two strokes ahead of Bryson DeChambeau (70).
The front nine at Winged Foot is one of the more daunting stretches in golf but a steadfast Wolff came out firing lasers at tricky pin positions and reached the turn with a blistering five-under 30 after five birdies.
Former Open champion Louis Oosthuizen (68) is the only other player in red figures at one under.
Hideki Matsuyama (70), Xander Schauffele (70) and Harris English (72) share fourth place on level par, with Rory McIlroy a shot further back after a 68.
Halfway leader Patrick Reed was alongside Wolff after nine holes, but the former Masters champion collapsed to a 77 after an inward half of 43 to be three over.
Hopes of another famous Australian victory at Winged Foot are over after disappointing rounds on moving day.
Adam Scott (74, nine over), Lucas Herbert (74, 10 over), Jason Day (76, 12 over) and Cameron Smith (78, 12 over) all fell well out of contention.
Victory on Sunday would make Wolff the first player to win the US Open on his debut since Francis Ouimet, 107 years ago to the day since the 20-year-old amateur defeated six-time Open champion Harry Vardon and two-time major winner Ted Ray in an 18-hole playoff.
Wolff is just a year older than Ouimet, turning professional in June 2019.
His unique, highly unorthodox swing is triggered with a pronounced flexing of the knees but is proving hugely effective in the biggest events after he finished fourth - behind 23-year-old Collin Morikawa - on his major debut in last month's US PGA Championship.
"I like to go out there and do what I feel comfortable with, rip dog and see how it goes from there," Wolff said.
DeChambeau, who began the day one shot back of Reed, made a bogey-bogey start but leaned on his power to chase down Wolff and squandered a chance to finish within one shot of the lead when he two-putted from six-feet for a closing bogey.
McIlroy has not given up on his bid to win a second US Open title, the four-time major winner getting within six shots of the lead.
"It was really good," McIlroy said of a round containing three birdies and one bogey.
"I executed the game plan really well, knocked a couple in when I could and yeah, a really good round of golf."
Australian Associated Press
