Erin, Wis. – Saturday at Erin Hills, a kid so skinny Wisconsinites were tempted to pelt him with cheese wheels walked off the course wearing bright pink pants, like he had lost a bet, and said he was shaking with hunger.

No need to feel sorry for the urchin. He had just shot a 63 in the U.S. Open.

Justin Thomas’ arms are the thickness of penne noodles, but he has the hip movement of an Olympic powerlifter. He overpowered Erin Hills on Saturday, breaking a U.S. Open record by recording a round of 9 under, and becoming the fifth player in tournament history to shoot a 63.

“You better go low if you’re going to wear these,” Thomas said.

He was talking about the hot-pink pants that successfully kept him from being mistaken for a deer by any Wisconsinites hunting out of season. Listed at 5-10 and 145 pounds, which may be correct when he is well-hydrated, Thomas put 10 threes on his scorecard Saturday, qualifying him to play for the Golden State Warriors.

Erin Hills has played so easily this week that Thomas’ record merely moved him into a three-way tie for second at 11 under, one shot behind Brian Harman. Sunday, he and each of the top 18 players on the leaderboard will try to his first major.

“Yeah, 63 was never on my mind,” Thomas said. “Tomorrow’s going to be fun.”

Thomas has won two PGA Tour events this year but has never finished better than 18th in a major. But with Tiger Woods and Phil Mickelson absent and Rory McIlroy, Dustin Johnson and Jason Day missing the cut, this week has at times felt more like a Safeway Open than a U.S. Open.

“The course is soft,” Thomas said. “And we’re really good.”

In person, Thomas, the 24-year-old from Louisville and the University of Alabama, does not look the part of a professional athlete. Unless you subscribe to golf magazines. Then you’d think he was chasing Nicklaus’ records.

He has appeared on recent covers of Golf and Golf Digest, showing off the a swing that generates remarkable power considering the size of the man wielding it.

Thomas is one of those modern golfers who swings as if he is keenly aware of his clubhead speed. He reached 63 by making eagle at the par-5 18th, and did so by hitting a 3-wood 330 off the tee, then cutting a 3-wood high and soft into the green from, he estimated, 310 yards out. That’s right — he eagled a hole that played at 667 yards without hitting his driver, then shrugged at his caddie like he expected to make a two.

“That was pretty sweet,” Thomas said.

Johnny Miller shot a 63 in the final round of the Open in 1973 at Oakmont. He did not sound impressed by the difficulty of Erin Hills.

“Nine under is incredible with U.S. Open pressure,” Miller told Golf Channel. “But it isn’t a U.S. Open course that I’m familiar with, the way it was set up.”

Despite the softness of the course, Thomas required a few spectacular shots to reach 63. On the par-4 No. 5, he knocked a putt away from the hole and into the fringe, then watched it roll down the slope and drop in. On the short par-4 15th, he hit a high 3-wood that landed past the hole, 288 yards away, then rolled back. He made birdie.

As he walked off the course, Thomas gave his ball to his father, who promised to build a special case for it. Thomas hopes to require more space for his own shrine, one that would fit the U.S. Open trophy.

“I’m not sure when it’s going to sink in or when I’m going to realize what I did,” he 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 little different feeling.”

Jim Souhan’s podcast can be heard at MalePatternPodcasts.com. On Twitter: @SouhanStrib. E-mail: jsouhan@startribune.com