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 compatriot 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 that included five birdies.

Former Open champion Louis Oosthuizen (68) is the only other player in red figures at one under.

The unorthodox swinging Matthew Wolff hits from the rough during his third round 65. PHOTO: Getty Images.

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.

Victory on Sunday would make Wolff the first player to win the US Open on 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.

RIGHT: Louis Oosthuizen is well placed to make a run at his second major championship title. PHOTO: Getty Images.

“I think that I go out there and I play my game. There's a lot of holes out there that maybe people would try to hit it in the fairway or maybe take the safe play because it is a US Open and they know that pars are a good score, but I don't really like to think of it that way,” replied Wolff, when asked if he would describe his play as fearless.

“I like to go out there and do what I feel comfortable with, rip dog and see how it goes from there. I feel comfortable with every part of my game, so I don't like to shy away from things when I'm feeling confident, and I'm probably going to do the same tomorrow.”

Wolff, already a winner on the PGA Tour, says he expects to be nervous about the final round but is looking to “just have a good time.”

“I bet you I'm probably going to be a little antsy. It's the US Open, and I have a lead,” Wolff said.

“You know, I'm going to try to keep my nerves as calm as they can be, relax tonight, not really try to think about it. I put myself in a really good spot. I did everything that I could do up until this point, and tomorrow I'm going to go out there, I promise you I'm going to try my best, and if I come out on top or not, it is what it is.

“But right now, I'm just looking to go have a good time, and it's just golf. Even though it is the US Open, there's a lot of things in life that are a little different right now, and in the world, you can see how many things are affecting us.”

Bryson DeChambeau punches out of the heavy rough during the third round at Winged Foot. PHOTO: Getty Images.

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.

“The round today was a huge battle. I was proud of the way I persevered out there today. It was difficult. Especially when you're not hitting it straight in the fairway. For me it felt like I kept myself in it, scrambled really well,” DeChambeau said.

THIRD ROUND LEADERBOARD

He may have to scramble hard again in the final round as he has vowed to maintain his aggressive game plan.

“I'm going to be aggressive no matter what,” he boasted. “It's if it's the right play. If it's the right wind, the right situation.

“Worst-case scenario, hitting hybrid out there in the middle of the fairway, and that's what has worked so far, but today it cost me a little bit. I didn't hit it in the fairway. You've just got to hit fairways out here.”

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."