Webb Simpson came close to shooting only the 10th sub-60 round on the PGA Tour during Thursday's opening round at The Greenbrier Classic before running out of steam.
Needing a birdie on each of his final two holes, the Players Championship winner capped his round with a pair of pars for a career-low, nine-under-par 61 at The Old White TPC in White Sulphur Springs.
Simpson's bogey-free round, which included seven birdies and an eagle at the par-5 12th, where he holed an 18-foot chip shot, left him one shot clear of South Korean Whee Kim and two clear of Chilean teenager Joaquin Niemann.
The former US Open winner blitzed the first seven holes on the back nine as he racked up four birdies and an eagle but then missed the fairway at 17 and left a birdie putt at the 18th about a foot short.
Jim Furyk broke golf's magic number when he shot a record 12-under 58 at the Travellers Championship in 2016, becoming the first player on the tour to break 60 twice.
Al Geiberger in 1977 was the first to post 59 on the PGA Tour, followed by Chip Beck (1991), David Duval (1999), Paul Goydos (2010), Stuart Appleby (2010), Furyk (2013), Justin Thomas (2017) and Adam Hadwin (2017).
Kim, still seeking his first win since joining the PGA Tour in 2015, mixed 10 birdies with two bogeys during a round where play was suspended for nearly two hours due to lightning in the area.
Phil Mickelson (66), making his first start since the US Open where he infamously ran down his bogey putt and struck the ball while it was still moving, was in a share of eighth place with defending champion Xander Schauffele.
Bubba Watson, who at number 12 is the highest-ranked player in the field, was in a distant share of 44th after a two-under-par 68.
The best of the Australian contingent was Cameron Percy, who shot a three-under-par 67 to end the day tied 24th.
The 44-year-old Victorian mixed five birdies with two bogeys to be three shots ahead of compatriot Steven Bowditch.