Mackenzie Hughes carded a superb 10-under 60 to steer the Vacationers Championship as Rory McIlroy made a robust begin.
Hughes holed 10 birdies within the first spherical at TPC River Highlands in Connecticut to open up a three-stroke lead on Thursday.
The Canadian, who has struggled since getting back from the coronavirus-enforced break, made six birdies on his first 9 holes earlier than choosing up pictures on the second, sixth, seventh and eighth holes.
Hughes is three pictures away from world No. 1 McIlroy, Xander Schauffele and Viktor Hovland.
McIlroy combined an eagle and 6 birdies with only a single bogey to start out with a seven-under 63.
Whereas Hughes is nicely clear, the remainder of the leaderboard is congested, with one other six gamers a shot additional again 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 stable begin with a three-under 67, to be alongside Jason Day and Justin Rose amongst others.
Spieth, winless since 2017, was 4 beneath via 9 holes earlier than a combined again 9, which included bogeys at 10 and 18.
Additionally in a tie for 33rd is Abraham Ancer, who produced the shot of the day with a hole-in-one on the 16th.
In the meantime, former world No. 1 Dustin Johnson opened with a first-round 69, two pictures higher off than countryman Justin Thomas.