Bud Cauley fired an eight-under 63 to take a two-shot lead after the opening round of the RBC Heritage, while Luke Donald made a strong start.
American Cauley produced a brilliant first round at Harbour Town Golf Links on Thursday, his eight birdies pulling him clear.
The 27-year-old birdied four of his final five holes - including his last three - to grab the lead in South Carolina.
Among a group of three tied for second is Donald, the Englishman carding a 65 that included an eagle at the par-five second.
The former world number one, now ranked 96th, is searching for his first win since 2013 and has finished second four times and third twice in his eight starts at the PGA Tour event.
Alongside Donald are Canadian Graham DeLaet and Sam Saunders, who both went through bogey-free.
American trio Russell Henley, Ben Crane and Webb Simpson are joined by England's Ian Poulter, Ireland's Shane Lowry and New Zealander Danny Lee a shot further back at five under.
Defending champion Branden Grace made a solid start, the South African's three-under 68 enough to have him tied for 19th.
Joining him at three under is two-time champion Jim Furyk and 2014 winner Matt Kuchar, who was tied for fourth at the Masters.