Canadian Mackenzie Hughes fired an error free 10-under 60 to take the first-round lead at the Travelers Championship in Cromwell, Connecticut, on Thursday, putting himself three shots clear of three players including world number one Rory McIlroy.
Playing the back nine first at the TPC River Highlands, Hughes was in blistering form as he strung together a run of five straight birdies from the 14th on his outward nine and picked up four more after the turn.
He had a long look at a magical 59 but left a 41-foot birdie putt short at his last.
"I've shot 61 twice in competition, once at Sea Island and once at a mini-Tour event," Hughes told reporters. "Both times there was an outside chance the last few holes to shoot 59.
"Kind of similar deal to today where I kind of needed to birdie the last few holes."
Also a back nine starter, McIlroy got off to a flying start by rolling in an 11-foot putt for an eagle on the par five 13th and then followed up with birdies at 14 and 15 to quickly get to four-under.
The Northern Irishman's only miscue was a bogey at 16 but he was error free the rest of the way, piling on four more birdies after the turn for a seven-under 63.
American Xander Schauffele and Norway's Viktor Hovland, who were part of the afternoon wave, finished tied with McIlroy after both carded seven-under 63s.
Lurking one shot further back is a pack led by Spain's Sergio Garcia and Phil Mickelson, who recently celebrated his 50th birthday, with both also enjoying error free starts.
Joining the two major winners at six-under are Americans Tyler Duncan and Michael Thompson plus South Korea's Noh Seung-yul and South African Louis Oosthuizen.
Golfers appeared to be taking heed and paying closer attention to COVID-19 safety protocols after PGA Tour Commissioner Jay Monahan issued a stern warning on Wednesday following the withdrawal of several players.
Major champions Brooks Koepka and Graeme McDowell pulled out of the event after their caddies tested positive for COVID-19 while Cameron Champ withdrew on Tuesday after testing positive.
(Reporting by Steve Keating in Toronto and Rory Carroll in Los Angeles; Editing by Ken Ferris)
