Through two rounds – one on each of Sea Island Resort's two courses – Cole Hammer, Andrew Putnam and Harry Higgs lead the RSM Classic field with a score of 12 under.

In a unique format, this tournament has half of the field play the par-70 Seaside Course and the other half play the par-72 Plantation Course in the first round, before swapping for the second round.

After earning the solo lead by shooting an eight-under 64 on Thursday's trip around the Plantation Course, Hammer still produced seven birdies on the Seaside Course, but three bogeys on the front-nine allowed others to join him at the top.

Both Higgs and Putnam shot rounds of seven under, albeit on different courses. Higgs went bogey-free for a 63 at the Seaside Course, and Putnam went bogey-free until his final hole, blowing a chance to head into the weekend with the outright lead.

Of the five players to shoot better than seven under on Friday, all five did it on the Plantation Course, including Joel Dahmen with his eight-under 64 to jump up to a tie for fourth at 11 under, where he is joined by Sahith Theegala.

The other eight-under rounds came from South Korea's Noh Seung-yul, tied for fourth at 10 under, as well as Ben Martin and Will Gordon, one further back at nine under.

The round of the day came from Akshay Bhatia, following his three-over 73 with a nine-under 63.

Some of the bigger names in the field will not be participating on the weekend as former world number one Jason Day missed the cut by three strokes, and former Masters champion Danny Willett withdrew after his three-over opening round.

The remaining two rounds will both be played at the Seaside Course.

Russell Henley carded the lowest 54-hole score of the season to pull six strokes clear at the final turn at the World Wide Technology Championship at Mayakoba on Saturday.

The 33-year-old American carded a six-under-par 65, following on from successive rounds of 63 to hold a significant advantage from the nearest contenders, Will Gordon and Patton Kizzire at 16 under. Henley has tallied 191 across the three rounds at El Camaleon Golf Club.

Only four players had a better third round than Henley, who went into the day's play with a three-shot lead. Henley's long putt for birdie on the par-three 15th hole was his 22nd birdie of the tournament.

Seamus Power, who won last week's Butterfield Bermuda Championship, enjoyed the round of the day with an eight-under 63 to be alone in third.

Power's round included four birdies and two eagles, with one of the latter being a 138-yard hole-in-one on the eighth.

The Irishman is behind Gordon and Kizzire at 15 under, with Troy Merritt and Brian Harman one shot behind at 14 under. Reigning back-to-back champion Viktor Hovland is a further stroke behind among a group of four players.

Greyson Sigg, who is 13-under overall, aced the 10th to join Power and make it two holes-in-one on the same day in excellent conditions.

Joel Dahmen went within a whisker of the second-ever hole-in-one on a par four in PGA Tour history, when his massive approach landed inches away from the flag on the 17th hole.

Joel Dahmen is a surprise co-leader with Collin Morikawa after 36 holes of the U.S. Open at The Country Club – and he was contemplating skipping the qualifier.

Dahmen, 34, is one of three players to shoot 68 or better in both rounds, finishing the first round one off the lead after a 67, before backing it up with a 68 on Friday. Hayden Buckley and Aaron Wise both posted a pair of 68s, and are one stroke off the lead in a tie for third.

In his second trip around the course, Dahmen had a strong front nine, birdieing the first hole as well as the fifth and eighth, with a bogey on the second. He started the back nine poorly, with a bogey on 10, but followed it with seven pars and a long birdie putt.

Speaking to the media after his round, he confirmed the story that he almost pulled out of the qualifier where he punched his ticket.

"There was a lot of discussion leading up to it, yeah, the prior week," he said. "I told my wife I wasn't going to do it.

"Then I was tired at Memorial and said I wasn't going to do it. I was never really going to do it until I… sort of played better at Memorial and the game was there.

"My coach, Rob Rashell, came out and things started to trend in the right direction. And then [my caddie] Geno [Bonnalie], I felt bad because he didn't switch his flight when he could have got home Sunday night, so at that point I had to stick it out."

Clearly, he is thrilled with his decision.

"I'm incredibly happy now for sure," he said. "I mean, sometimes you take for granted what you have out here a little bit. 

"I think this is my eighth or ninth major championship, and you think not long ago I would have done a lot of things to play in one, and to think that I have an opportunity just to skip one, kind of looking back, even this whole week, you don't appreciate really.

"I've played 130-odd events. I've been six years out here. It's easy to get in a lull and be like, you just go home for two weeks and hang out and everything is all hunky-dory, but when you get here, everything changes as soon as you get on property. 

"It's a USGA event. It's huge. People everywhere. So, yeah, that changes your mind pretty quickly."

After finding some form recently, Dahmen said he is starting to encounter fans who know who he is – something he does not believe will ever feel normal.

"It is unbelievable to me how many people know my name or yell for me out there," he said. "It's weird. 

"I'm getting recognized a little bit more off the golf course – my wife will look at me, like, what is happening? 

"It's not normal. I don't know if I'll ever get used to it, but it comes with good golf."

Joel Dahmen is a surprise co-leader with Rory McIlroy after 36 holes of the U.S. Open at The Country Club – and he was contemplating skipping the qualifier.

Dahmen, 34, is one of three players to shoot 68 or better in both rounds, finishing the first round one off the lead after a 67, before backing it up with a 68 on Friday. Hayden Buckley and Aaron Wise both posted a pair of 68s, and are one stroke off the lead in a tie for third.

In his second trip around the course, Dahmen had a strong front nine, birdieing the first hole as well as the fifth and eighth, with a bogey on the second. He started the back nine poorly, with a bogey on 10, but followed it with seven pars and a long birdie putt.

Speaking to the media after his round, he confirmed the story that he almost pulled out of the qualifier where he punched his ticket.

"There was a lot of discussion leading up to it, yeah, the prior week," he said. "I told my wife I wasn't going to do it.

"Then I was tired at Memorial and said I wasn't going to do it. I was never really going to do it until I… sort of played better at Memorial and the game was there.

"My coach, Rob Rashell, came out and things started to trend in the right direction. And then [my caddie] Geno [Bonnalie], I felt bad because he didn't switch his flight when he could have got home Sunday night, so at that point I had to stick it out."

Clearly, he is thrilled with his decision.

"I'm incredibly happy now for sure," he said. "I mean, sometimes you take for granted what you have out here a little bit. 

"I think this is my eighth or ninth major championship, and you think not long ago I would have done a lot of things to play in one, and to think that I have an opportunity just to skip one, kind of looking back, even this whole week, you don't appreciate really.

"I've played 130-odd events. I've been six years out here. It's easy to get in a lull and be like, you just go home for two weeks and hang out and everything is all hunky-dory, but when you get here, everything changes as soon as you get on property. 

"It's a USGA event. It's huge. People everywhere. So, yeah, that changes your mind pretty quickly."

After finding some form recently, Dahmen said he is starting to encounter fans who know who he is – something he does not believe will ever feel normal.

"It is unbelievable to me how many people know my name or yell for me out there," he said. "It's weird. 

"I'm getting recognized a little bit more off the golf course – my wife will look at me, like, what is happening? 

"It's not normal. I don't know if I'll ever get used to it, but it comes with good golf."