Thomas and Miller are the only players to shoot a 63 in U.S. Open history.
Johnny Miller had maintained the record with the 8-under 63 he shot during the 1973 U.S. Open. Fans will be following him in droves Sunday as he tries to win his first major championship.
"I'm not sure when it's going to sink in or when I'm going to realize what I did", Thomas said.
Grass stains from forays into the rough and claustrophobia from narrow fairways have been replaced by grins and giggles, as a run-of-the-mill PGA Tour event has taken over what is typically one of the most exhausting tests on the golf calendar.
"I don't think I could play any different or score any better than I have done".
Thomas, however, is not alone in that pursuit.
Fleetwood had been tied for the lead after birdies on the first, eighth, 12th, 14th and 15th, only to bogey the last after following up a poor pitch by putting his birdie attempt off the green. "If I'd dropped more shots it would've left a very sour taste".
"We're going to have a good time", Fowler said.
Harman narrowly missed a birdie putt on the par-5 18th hole. There were five players in double digits Saturday at Erin Hills. "It could change in a heartbeat".
Pink trousers and all, Thomas hit the putt perpendicular to the hole, and somehow sunk it for a birdie. What slowed him on Saturday was a triple bogey on the third hole, but conditions were so tough that Woods shot even-par 71 and still increased his lead to 10 shots.
Today I felt like I was hitting away from the pin a lot because of where they were. "But you can't do anything about that stuff". On the last hole I was miles out on the fourth shot and could've been looking at a seven or an eight but I hit a great chip to get a six.
Rickie Fowler, urged on by the biggest galleries at Erin Hills, turned in a scrappy outward nine mixing two birdies with a bogey to sit three back of the leader. But those errors were comfortably outweighed by nine birdies and a spectacular eagle at the par-five 18th, where he hit his approach shot to eight feet from 299 yards.
Harman, bidding to become the first left-hander to win a US Open, is a victor on the PGA Tour this year while Thomas is the world number 13, a three-time victor this season and a member of the exclusive "59" club after breaking 60 at the Sony Open this year. At Erin Hills you barely would have made the cut at 1-over, and if Sunday is anything like the previous three days, someone is going to have to shoot in the low 60s to win, unless Mother Nature decides to rear an angry face.