Scottie Scheffler is the low amateur for this year's U.S. Open.
Fleetwood and Harman still had most of their back nines to play as Thomas relaxed in the clubhouse and reflected on his record round. Going into the final round, 42 players were still under par.
Fowler was among those who wouldn't mind seeing the conditions toughen up for the final 18 holes.
One stroke back are a trio of Americans in J.B. Holmes, Jamie Lovemark and first-round leader Fowler. That's the lowest differential after 36 holes in the U.S. Open, mainly because until 2012, everyone within 10 shots of the lead made the cut at the U.S. Open. Champ is 3 over in the final round with two holes to play. He dropped nine shots over the next seven holes - three double bogeys, three bogeys and one par. He went from a tie for second at the beginning of the day to a tie for sixth.
Greg Norman and Vijay Singh are the only golfers to record two rounds of 63 in the majors.
Thomas broke new ground with a sensational performance in round three - his nine-under 63 representing the lowest score to par in U.S. Open history. His 1-over-73 left him in a tie for 51st at 2 over through 54 holes.
The 40-year-old Hoffman is playing in his sixth U.S. Open. The soft Black Course allowed players to take dead aim, and Barnes opened with rounds of 67 and 65.
"It was a good bogey though", joked Fleetwood, who regained his composure to hit a superb pitch from well below the putting surface.
Harman was on top at 12 under coming into the day. 10 and 11, then made five more pars before making a birdie on No. 17.
McIlroy finished eight shots ahead of Jason Day, whose score of 8-under 276 would have been enough to win 26 of the previous 30 U.S. Opens. Then again, Spieth has always said Ellie is the funniest member of the family.
He recovered to drain a 13-foot birdie putt on the par-three 13th, but thereafter was unable to build any momentum over the remainder of the opening nine holes.
Patrick Reed has joined the 65 club at Erin Hills.
The lead, however, belonged to Brian Harman. Results are not what will make this a great week at Erin Hills for the 50-year-old Stricker. It features a silhouette of Palmer in mid-stride, tossing his visor in the air. He tees off later on Sunday.
Thomas eagled the par-5 18th at Erin Hills, cementing his place in history.
A whopping eight players are at 6 under, including world No. 4 Hideki Matsuyama and Louis Oosthuizen.
Morgan shot 77 and, remarkably, still had the lead at 4-under 212.
Fowler came back to birdie the par-3 ninth to get back to one shot back.
The wind is gusting up to 25 miles per hour with the forecast calling for it to go as high as 30 miles per hour in the afternoon when the leaders tee off.
Rickie Fowler's housemate just had to show him up on Saturday.
Spieth's day at the course likely isn't done.
Two other times that Thomas was in trouble, he emerged with birdies.
Nobody in the top 16 on the leaderboard has won a major.