ERIN, Wis. -- Justin Thomas became just the fifth player to shoot 63 in a U.S. Open when he eagled the 18th hole from 8 feet at Erin Hills on Saturday.
Thomas, 24, who shot 59 earlier this year in Hawaii, was 9 under on the par-72 course, eclipsing the U.S. Open record for lowest round in relation to par, set by Johnny Miller at Oakmont (par 71) in 1973.
Thomas will begin the final round Sunday one shot behind leader Brian Harman, whose 5-under 67 propelled him to a 12-under 204 total.
"Yeah, 12 under, I'd have about a 10-shot lead in most Opens," Harman said.
"It means I'm a part of history," Thomas said after his round. "It means I have a lot better chance to win the tournament than I did when the day started. It's all pretty self-explanatory, I guess, in terms of what it means.
"For me, I felt like I've been playing pretty well all week and didn't quite have the numbers to show for it. Obviously, today I definitely had something to show for it."
Miller, whose 8-under 63 came in the final round, and Jack Nicklaus (1980, Baltusrol) are the only players to shoot 63 in a U.S. Open and win. Tom Weiskopf also shot 63 in the opening round of the 1980 U.S. Open at Baltusrol. Vijay Singh was the last player to do so during the second round of the 2003 U.S. Open at Olympia Fields.
It was the 31st score of 63 in major championship history. There were three in 2016, including a final-round 63 by Henrik Stenson in winning The Open at Troon.
No player has ever gone lower in a major.
Only six players had ever reached 10-under par or lower in the previous 116 U.S. Opens. There are five players in double digits at Erin Hills.
Koepka posted a 68 after reaching the green in two on the 667-yard closing hole for a two-putt birdie. Fleetwood was poised to take the lead until his pitch to the 18th wasn't strong enough and his next shot went beyond the flag and down the slope some 70 feet away. He got that up-and-down for a bogey and a 68.
Fowler, sharing a house with Thomas this week, was being left behind until he ran off three straight birdies and shot 68. He was 10 under.
"It's going to be a really cool day for someone tomorrow," Fowler said. "I'm looking forward to my shot at it. I've been there a handful of times and had some good finishes. But I'm looking forward to getting the job done."
Thomas made an eagle, nine birdies and two bogeys. He played the front nine in 31 with three straight birdies to finish then played the last seven holes in 5 under. He had 10 scores of 3 on his card and a 2.
"It doesn't matter how long, how whatever the course is," Thomas said about the longest course in major championship history. "When you give us soft greens, good greens and not much wind, you know there are going to be some good scores. I was just happy that I was the one that was able to take advantage of it today."
Thomas hit a 3-wood from 310 yards on the par-5 18th to set up his eagle putt.
"I knew it was for 63," said Thomas, who has won four times on the PGA Tour, including three this season. "You've got leaderboards everywhere, and for the most part you usually have an idea what you're doing.
"I told Jimmy [Johnson, his caddie] walking up there, once I found out we had a putt ... I said, 'Let's try to become a part of history here.' He said, 'Yeah, let's do it.'
"But I had no idea in terms of 9 under being the best in the U.S. Open."
Of the five other players who shot a 63 in the third round at a major, none went on to win. Most of them had to come from far back going into the weekend, and it was difficult to put together two good rounds.
Then again, none of the top 16 on the leaderboard has ever won a major.
Said Fowler: "Someone has a very good chance of ending up with their first major tomorrow."
Information from The Associated Press was used in this report.