Matt Wallace carded eight birdies in a six-under-par 64 to claim a share of the lead after the first round of the RSM Classic.
The 30-year-old bounced back from the frustration of his closing 77 at the US Masters last weekend to set the pace at Sea Island, Georgia, alongside Colombian Camilo Villegas.
Ireland's British Open champion Shane Lowry is three shots off the lead on three under having also played the Seaside Course. Tommy Fleetwood is also three under while Graeme McDowell and Justin Rose, who began on the Plantation Course, were two under.
Both Wallace and Villegas were playing the Seaside Course, one of two being used in the tournament along with the Plantation Course.
Wallace had to overcome late disruption to his plans after regular caddie Dave McNeilly tested positive for Covid-19.
Playing with assistance from a local caddie, he started with back-to-back birdies before dropping one of only two shots on the third. He picked up three more birdies on the front nine and another three coming home, with his only other blemish coming with a bogey at the par-four 14th.
Villegas, who played the back nine first, had six birdies in a bogey-free round.
Rory Sabbatini, who now represents Slovakia, was among a group of eight players on five under par after opening with four successive birdies.
Collated first round scores and totals (USA unless stated, par 70):
Seaside Course
64 Matt Wallace (Eng), Camilo Villegas (Col)
65 Peter Malnati, Rory Sabbatini (Svk), Patton Kizzire, Robert Streb
66 Emiliano Grillo (Arg), Alex Noren (Swe), Zach Johnson, Bernd Wiesberger (Aut), Harris English
67 Roger Sloan (Can), Matt Jones (Aus), Kyle Stanley, Shane Lowry (Irl), Tommy Fleetwood (Eng), Cheng-Tsung Pan (Tai), Corey Conners (Can)
68 Charley Hoffman, Austin Cook, Nate Lashley, Bronson Burgoon, Webb Simpson, Bol Hoag, Sebastian Cappelen (Den), Brendon Todd, J.J. Spaun, Jim Herman
69 Jason Day (Aus), Scott Brown, Danny Willett (Eng), Tom Hoge, Hunter Mahan, Tyrrell Hatton (Eng), Ian Poulter (Eng), Keith Mitchell, Brice Garnett, Henrik Stenson (Swe)
70 Chris Kirk, Branden Grace (Rsa), Cameron Davis (Aus)
71 Andrew Putnam, Vincent Whaley, Sepp Straka (Aut), Charl Schwartzel (Rsa), Jason Dufner, Sung Kang (Kor), Lucas Glover, Kyoung-hoon Lee (Kor), Tim Wilkinson (Nzl), Denny McCarthy, Michael Hebert, Ryan Armour, Joseph Bramlett, Kyung Ju Choi (Kor), Will Gordon
72 Brendan Steele, Kevin Stadler, Hudson Swafford, Russell Knox (Sco), Matthew Fitzpatrick (Eng), D.J. Trahan, Chez Reavie
73 Richy Werenski, Nick Taylor (Can)
74 Joey Garber, Mark Hubbard, Kevin Tway, Stewart Cink, Troy Merritt
75 Nick Watney, Jason Kokrak, Xinjun Zhang (Chn), Jamie Lovemark
76 Sebastian Munoz (Col), Lee Westwood (Eng)
77 Maverick McNealy
Plantation Course:
67 Keegan Bradley, Adam Long, Doug Ghim, Cameron Tringale
68 Aaron Baddeley (Aus), Andrew Landry, Rhein Gibson (Aus), Kevin Kisner, Charles Howell III
69 Scott Stallings, John Huh, Patrick Rodgers
70 Graeme McDowell (Irl), Vaughn Taylor, Scott Piercy, Matt Kuchar, Wyndham Clark, Sean O'Hair, Justin Rose (Eng), Russell Henley
71 JT Poston, Talor Gooch, Kevin Chappell, Rafael Cabrera-Bello (Spa), Kevin Streelman
72 Matthew NeSmith, Christopher Baker, Brian Harman, Doc Redman, James Hahn, Ryan Brehm, Luke Donald (Eng), Sungjae Im (Kor), Jonathan Byrd
73 Adam Schenk, Sam Ryder, Chesson Hadley, Louis Oosthuizen (Rsa), Matt Every, Mark Anderson, Andy Sullivan (Eng), Joaquin Niemann (Chi), Hank Lebioda, Rob Oppenheim, Scott Harrington, Bol Van Pelt, Mackenzie Hughes (Can), Josh Teater
74 Brian Stuard, Luke List, Pat Perez, Brandon Hagy, David Hearn (Can), Joel Dahmen, Ted Potter, Jr, Martin Laird (Sco), Martin Trainer, Brandon Crick
75 Kristoffer Ventura (Nor), D.A. Points, Satoshi Kodaira (Jpn), Harold Varner III, Harry Higgs, Tyler McCumber, Jhonattan Vegas (Ven), Cameron Percy (Aus)
76 Chase Seiffert, Aaron Wise, Beau Hossler, Adam Hadwin (Can), Tyler Duncan, Dylan Frittelli (Rsa), Brandt Snedeker
77 Davis Thompson
78 Robby Shelton, Anthony Cordes, Fabian Gomez (Arg)
79 Michael Gligic (Can)
