ERIN, Wis. — A U.S. Open short on big names and a leaderboard that at times seemed like a phone book of random people found a bright star Saturday under a partially cloudy sky at Erin Hills.

Justin Thomas made history when he shot a 63, a nine-under score that was the lowest relative to par in U.S. Open history. And the 63 tied the Open mark set by Johnny Miller at Oakmont in 1973, and equaled by Jack Nicklaus and Tom Weiskopf (1980) and Vijay Singh (2003).

As good as that round was, Thomas has not run away with the tournament. In fact, he’s not even leading after three rounds.

Brian Harman has a one-shot lead at 12 under. Tied with Thomas at 11 under are Brooks Koepka and England’s Tommy Fleetwood. Rickie Fowler is at 10 under.

“I’m not sure when it’s going to sink in or when I’m going to realize what I did,” Thomas said. “I know one thing, if it happened tomorrow and the result is what I want it to be, then I’d probably have a different feeling. I’m just so excited to give myself a great chance to win this golf tournament.”

Thomas’ most dramatic moment happened on the 667-yard, par-five 18th hole when he hit his three-wood second shot more than 300 yards. The ball hit just short of the green, popped forward and rolled eight feet past the hole.

“I obviously needed to nuke it,” Thomas, 24, said of his three-wood, which he later called his best of the round. “But I just felt like I could get it up in the air enough to hold the green, as soft as they were. And it came out nicely.”

After waiting while playing partner Jonathan Randolph hit his third, fourth, fifth and sixth shots, Thomas rolled in his putt for an eagle.

“I was excited to take the lead,” Thomas said. “I was excited to shoot 63. I had no idea that nine under was the best ever in an Open, so that was pretty cool once I saw my card. The guys at the scoring table told me that, so I was pretty pumped.”

Thomas started his record round with birdies on the first two holes. On No. 1, a par five, he was 85 feet short of the hole on his second shot and got the easy up and down. On the 331-yard second hole, his drive was 46 feet short of the hole and, again, he got up and down.

He gave back a stroke on No. 4 when his drive went into the right fescue and his second shot was over the green. He birdied the fifth with a 19-foot putt that he started from off the green in the opposite direction of the cup.

After parring the sixth, he had a run of three birdies. On No. 7, he sank a 15-footer. On No. 8, he drilled his 154-yard approach shot to about two feet. And on No. 9 he made a 21-foot putt.

He bogeyed the 10th hole when he hit a bad second shot right of the green. Then he picked up a birdie on No.12 with a nine-foot putt. He drove the green on the 288-yard, par-four 15th and just missed a short eagle putt. He made a 27-footer for birdie on No. 17 before the history-making finish.

The Louisville native is not new to success. He won the first two tournaments of this year, both in Hawaii. In the Sony Open he became the seventh player to shoot a sub-60 round with a 59. He won that tournament by seven shots.

There were a lot of low scores Saturday. The course took an inch of rain overnight, making it about as menacing as a golden retriever puppy. Thirty-two players had sub-par rounds, the most for the third round of an Open.

“It was definitely conducive for good scores today,” Thomas said. “When you give us soft greens and not much wind, you know there are going to be some good scores. I was just happy that I was the one to take advantage of it today.”

Harman, who is hoping to become the first left-hander to win the U.S. Open, must have felt overlooked given Thomas’ accomplishment. But, obviously, his 67, with six birdies and one bogey, was a pretty good round.

He had a chance to extend his lead to two but missed an 11-footer for birdie on 18.

“I’m motivated by the fact that I’ve made a plan and I’ve stuck to the plan so far,” Harman said. “Obviously, I have no idea what (Sunday) holds, but I’m more motivated by the way I’m striking the ball. It’s the best I’ve struck the ball in a long time. And my short game is pretty good. I’ve been putting it pretty good. So I’m excited about all those things.”

Harman, 30, joined the PGA Tour in 2012 and has won two tournaments, including the Wells Fargo Championship this year.

There are 15 players within six strokes of Harman, so it’s still a wide-open tournament.