American Bud Cauley carded a first-round 63 to take an early lead at the RBC Heritage in Hilton Head, SC.
Cauley recorded four birdies on the front nine and four more on the back without a bogey en route to an 8-under par, two shots ahead of England's Luke Donald, Canada's Graham DeLaet and American Sam Saunders. Six others sit three shots off the pace.
Cauley's 63 was one over his personal best and two more than the tournament record of 61 shared by David Frost (1994) and Troy Merritt (2015).
"You never go out thinking you're going to shoot that," Cauley said after finishing out his round with birdies on four of the final five holes. "I just got into the round and was swinging well and tried to give myself as many looks as I could."
Cauley missed the cut in two of his previous three appearances at the RBC Heritage and has never finished better than third on the PGA Tour.
South African and reigning champion Branden Grace, who went on to win after posting a first-round lead in 2016, is tied for 19th with a 3-under 68. Americans Jim Furyk and Matt Kuchar and German Martin Kaymer join Grace in a large group at 3-under.