One shot back. Jamie Lovemark. Rickie Fowler accomplished the feat in the first round, and Hideki Matsuyama and Chez Reavie hit the number Thursday.
Among them all you won't find one victor of a major and only Fowler with star power.
The one thing all of these golfers have in common?
But not long after he signed for his record score and an 11-under 205, he began to appreciate the significance of a 63 on this day.
Then, inexplicably, he lost his putting touch. Jordan Spieth was even par through 12 holes and going nowhere. For all his good work, the Englishman needed a flawless pitch shot to save his round.
He three-putted on No. 13.
Casey was the only leader who went in the morning. Henley's bogey-free round included hitting 16-of-18 greens in regulation and four birdies on the back nine. No harm, no foul. He then backed it up with a second-round 64 and holds the tour scoring records for 36, 54 and 72 holes. It didn't get any better when he finally made the green. 14 and 15 to get to 12-under.
"He loves golf. He actually wants a new driver or something, but I think we can find him something in the shop at the end of the day", Jonas said. "Yeah, it was a bit of a roller coaster".
"We had two other guys shoot in the 60s that day", Miller said.
LOUIS LOUIS: For a while Saturday, Louis Oosthuizen looked as if he would make one of the biggest moves up the leaderboard after shooting a 68 in the third round to move to 4 under.
McIlroy was never in the short grass from the 11th hole to the end on Thursday when he opened with a career-worst 78, and he didn't do almost enough in the second round until it was far too late.More news: Ireland's DUP deal with UK PM May not likely before next week
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"I'll take exactly where I'm at", Fowler said.
Third-round disappointment aside, Cink is still looking forward to playing on Sunday.
His first four holes went this way: double bogey, bogey, bogey, bogey.
Fleetwood found his way to the top with a rather ordinary four-birdie, two-bogey round.
The 26-year-old, twice a victor on the European Tour, was delighted to be in contention.
Nick Rogness felt as nervous as anyone at the U.S. Open - not because of a golf club in his hand but the diamond ring in his pocket.
"It's going to be a really cool day for someone tomorrow", Fowler said. "Anything can happen. There are always ups and downs out there". At 30, Harman has been around long enough to claim two PGA victories.
Marc Leishman has surged up the leaderboard with a hot front nine during the third round of the US Open on Saturday.
"I have no expectations", he said.
"Well, it would change my life", he said. And I feel like once the can gets open, I'll start pouring them in.
"Someone has a very good chance of ending up with their first major tomorrow", Fowler said.
Rain is expected Saturday, which should make the greens easy to stick and putt.
Another 63 is perhaps unlikely, because the breeze is finally predicted to pick up on Sunday, perhaps offering a stern test, though the course will probably remain fairly soft.
Whatever happens, the championship is set to crown a first-time major victor, as the closest previous major champion is Louis Oosthuizen in a tie for 17th at four-under.