Rod Pampling flirted with a 59 before settling for a two-shot lead as the first round of the Shriners Hospitals for Children Open was suspended.
The Australian produced a stunning 11-under 60 at TPC Summerlin in Las Vegas, Nevada on Thursday.
Pampling holed two eagles and seven birdies, but pars on his final two holes saw him miss out on joining the 59 club.
He holds a two-shot lead from American pair Brooks Koepka and John Huh, who opened with 62s, after darkness suspended play.
Billy Horschel (64) is outright fourth, ahead of Australian Matt Jones, American Luke List and Spaniard Jon Rahm.
Rahm is the highest placed player yet to finish his opening round, still with two holes to play.
But the day belonged to Pampling, whose last of two PGA Tour wins came in 2006.
He had four birdies and an eagle on the front nine and was 11 under when he eagled the 16th.
Only six players - Jim Furyk the last at the 2013 BMW Championship - have shot 59s on the PGA Tour.
Defending champion Smylie Kaufman carded an even-par 71 to be tied for 84th.