Los Angeles - Justin Thomas eagled his final hole to card a rare 59 in the first round of the USPGA Tour Sony Open in Hawaii on Thursday.
Thomas, winner of the Tournament of Champions on Sunday at Kapalua, rolled in a 15-foot eagle putt at Waialae's Country Club's ninth hole to finish the first round on the par-70 layout at 11-under.
The 23-year-old American became the seventh player - and the youngest - to post a sub-60 round on the US tour.
"It was obviously a fun day," said Thomas, whose spectacular effort gave him an early five-shot lead in the opening round of the US PGA Tour's first full-field event of 2017.
With afternoon starters still on the course, Americans Russell Henley, Gary Woodland and Tony Finau, Scotland's Russell Knox and Australian Cameron Smith had all made it into the clubhouse on 64.
"I just kind of had it rolling out there," Thomas said. "All my birdies were easy - it wasn't like I made any long putts or anything."
But Thomas wasn't blind to the significance of the number.
"We all know it's the magical number in golf," he said.
Most recently, Jim Furyk carded a record 58 at the Travelers Championship in Connecticut in August.
Furyk also has a 59 on his tour resume, as does Al Geiberger, Chip Beck, David Duval, Paul Goydos and Australian Stuart Appleby.
Thomas had opened his round with an eagle at the 10th, where he hit his tee shot 315 yards and holed out from 34 yards out in the fairway for a two.
He had eight more birdies and a bogey on the day, and kept his sizzling form going with a nine-foot par-saving putt at the eighth.
"That save on eight was huge," Thomas said. "It gave me a chance because I knew if I hit a good drive on nine I was going to have a seven- or eight-iron in."
But his drive at the par-five ninth found the bunker.
"I missed it by six inches of carrying the bunker," said Thomas, who first thought he'd have to just hit a wedge out, but with a perfect lie went with a five-iron and got it to the green.
"I got a good read and it just hung on there enough to go in," he said.
Playing partners Jordan Spieth and Daniel Berger looked almost more excited than Thomas when the putt dropped.
"I was calm," Thomas said.
"I wasn't too nervous over the putt, I was just focused on making the putt.
"I got more excited from seeing them get excited than I did my putt going in."
Thomas, whose third PGA Tour victory on Sunday lifted him to a career-high 12th in the world, said the moment felt a little odd.
"It's not like winning the tournament you know," he said.
"It's like, hey, unbelievable round - you have three days left still. So I didn't really know how to react."
Spieth, a friend and former junior and college rival of Thomas, opened with a 65 and was happy to have a ringside seat to his buddy's stellar performance.
"I'm just really, really happy for JT right now," Spieth said.
"It's history, it's awesome, it's really cool ... to be able to watch it today."
Leading first-round scores on Thursday in the USPGA Tour Sony Open at Waialae Country Club in Honolulu, Hawaii (USA unless noted):
59 - Justin Thomas
62 - Hudson Swafford
63 - Rory Sabbatini (RSA)
64 - Russell Henley, Russell Knox (SCO), Gary Woodland, Tony Finau, Cameron Smith (AUS), Jamie Lovemark, Billy Hurley, Shawn Stefani
65 - Richy Werenski, Jason Dufner, Vijay Singh (FIJ), Daniel Berger, Jordan Spieth, Jon Curran, Michael Thompson, Charles Howell, Satoshi Kodaira (JPN)
66 - Sean O'Hair, Will MacKenzie, Soren Kjeldsen (DEN), Stewart Cink, Jim Herman, Brian Stuard, Jason Bohn, Boo Weekley, Ryan Palmer, Daniel Summerhays, Brian Harman, Ollie Schniederjans, Ben Martin, Webb Simpson, Justin Rose (ENG), Hideki Matsuyama (JPN), Scott Piercy