Camilo Villegas produced a sparkling eight-under-par 63 to claim the first-round lead in the Wyndham Championship at Sedgefield Country Club in Greensboro, North Carolina.
Americans William McGirt and Webb Simpson - the 2011 Wyndham champion - must have thought they had done enough to head into day two of the final regular event of the PGA Tour season at least top of the pile, but Colombian Villegas had other ideas to lead the duo by a shot at the end of play.
Villegas started as he meant to go on with a birdie at the 10th - his first hole of the day - and went on to add four more birdies and a brilliant eagle three at the par-five fifth to highlight a flawless opening round.
England's Paul Casey, Scotland's Martin Laird and American trio Scott Langley, Heath Slocum and Andrew Loupe were two shots off the pace after signing for 65s.
Pádraig Harrington, however, struggled to make an impression throughout his round and ended the day two over par with a 72.