Canadian golfer Adam Hadwin became the eighth player to break 60 on the US PGA Tour, and the second in successive weeks.
Hadwin shot a 13-under 59 on Saturday to lead the CareerBuilder Challenge in La Quinta, California.
He holds a one-stroke advantage over American Dominic Bozzelli, who shot a three-under 69.
Hadwin's brilliant round comes nine days after American Justin Thomas fired an opening 59 at the Sony Open in Hawaii.
"I got away with a few shots on the back (nine) and, for whatever reason, whenever I hit a putt, it went in ... I legitimately thought about it (shooting 59) on 11, walking off (the green)," Hadwin told the Golf Channel.
The 29-year-old Hadwin from Saskatchewan, who has yet to win on the PGA Tour, reeled off six consecutive birdies from the second hole as he raced to the turn in seven-under 29, and then plundered five in a row from the 11th.
After narrowly missing a birdie attempt at the 16th, Hadwin struck a brilliant approach to five feet at the par-four 17th and knocked in the putt to tie a PGA Tour record with his 13th birdie of the round.
He did well to salvage a par at the 18th, getting up and down from just off the back of the green, sinking a four-footer to become the latest member of the '59' club.
Geoff Ogilvy remained in the mix, with the Australian firing a round of 68 to be five shots off the lead at 12 under.
Five-time major winner Phil Mickelson, the biggest name competing this week, carded an erratic 73 to end the third round joint 21st at nine under.
