Mackenzie Hughes carded a brilliant 10-under 60 to lead the Travelers Championship as Rory McIlroy made a strong start.
Hughes holed 10 birdies in the first round at TPC River Highlands in Connecticut to open up a three-stroke lead on Thursday.
The Canadian, who has struggled since returning from the coronavirus-enforced break, made six birdies on his first nine holes before picking up shots at the second, sixth, seventh and eighth holes.
Hughes is three shots clear of world number one McIlroy, Xander Schauffele and Viktor Hovland.
McIlroy mixed an eagle and six birdies with just a single bogey to start with a seven-under 63.
A 7-under 63 for @McIlroyRory in Round 1 @TravelersChamp.
— PGA TOUR (@PGATOUR) June 25, 2020
Highlights from his first round: pic.twitter.com/3sHpx62l54
While Hughes is well clear, the rest of the leaderboard is congested, with another six players a shot further back in a tie for fifth.
Phil Mickelson, Sergio Garcia, Michael Thompson, Tyler Duncan, Noh Seung-yul and Louis Oosthuizen opened with 64s.
Jordan Spieth made a solid start with a three-under 67, to be alongside Jason Day and Justin Rose among others.
Spieth, winless since 2017, was four under through nine holes before a mixed back nine, which included bogeys at 10 and 18.
Also in a tie for 33rd is Abraham Ancer, who produced the shot of the day with a hole-in-one at the 16th.
My first ACE on the @PGATOUR today! Lezzgoo! Too bad cameras weren’t on for the shot. #TeamAncer @TravelersChamp pic.twitter.com/A3ozsccENS
— Abraham Ancer (@Abraham_Ancer) June 25, 2020
Meanwhile, former world number one Dustin Johnson opened with a first-round 69, two shots better off than countryman Justin Thomas.