John Catlin carded the first sub-60 round in Asian Tour history on Saturday, his 11-under-par 59 catapulting him into the lead at the International Series Macau.
The American rolled home a curling, left-to-right 15-foot putt on the final green for an eagle three as he moved to 18 under par after three rounds.
"I never, never, never thought I'd shoot 59," said a delighted, but slightly stunned, Catlin.
He has a two-shot cushion over LIV Golf's Jason Kokrak, who carded an eight-under-par 62, at the top of the leaderboard at the $2 million event with one round to play.
Catlin, who was the Asian Tour player of the year in 2018, got off to a blistering start in his third round, draining six birdies for a front nine of 28 on the par-70 coastal layout at Macau Golf and Country Club.
He sank three more on the 11th, 13th and 17th before his beautifully judged eagle on the 564-yard, par-five 18th capped a historic round of golf.
"I didn't realise I shot 28 on the front nine so the magic number wasn't really in my head until the 17th," said Catlin.
"It's a 239-yard par three, downhill 41 yards, so you're not really trying to make a birdie.
"It actually got a little closer than I was trying," he smiled.
"I was able to bury that one and I figured, well, three down the last. And just hit two beautiful shots in there.
"The putt was a big, left-to-right swinger and I just happened to get the pace and the line right."
Sub-60 rounds are extremely rare in golf.
There have only been 12 on the US PGA Tour, one on the LPGA Tour, one on the European Tour, two in LIV Golf and until Saturday, none on the Asian Tour.
It was a remarkable return to form for Catlin, who has been in a slump since the end of 2022 and lost his DP World Tour card in 2023.
"After all I've been through in the last two years, it hasn't totally sunk in yet," said Catlin.
"You sacrifice a lot and you put in a lot. I definitely want to thank my coach, Noah Montgomery, he's been with me now for 10 years and he really helped me through it," said Catlin.
"I don't know where I'd be if I didn't have him in my corner," added Catlin, who was awarded a special invitation by the Asian Tour to play in Macau.
"We just kept pushing. And yeah, it's pretty, pretty special."
Kokrak's bogey-free 62 contained six birdies and an eagle.
"I didn't drive it quite as good as I did yesterday, but the putter cooperated," said Kokrak.
Overnight co-leader Jbe Kruger had a four-under 66 to lie three behind Catlin on 15 under, the same mark as Australia's Lucas Herbert who also had a 62.
But Spain's David Puig, who started the day joint top of the leaderboard, fell back with a scrappy 68 containing four bogeys, and now lies in a share of eighth place on 13 under par.