Robert Streb will carry a record-equalling three-stroke lead into the final round of the RSM Classic.
Champion in 2014, Streb carded a three-under 67 in the third round on the Seaside course at the Sea Island Golf Club in Georgia on Saturday.
The American moved into 17 under and his three-stroke lead tied the record for the largest 54-hole advantage in tournament history.
Streb, whose only previous PGA Tour victory came at the same event in 2014, produced a bogey-free third round that included three birdies.
Zach Johnson (65) and Bronson Burgoon (67) are Streb's nearest challengers at 14 under.
Emiliano Grillo produced a fast finish with an eagle and two birdies on his final four holes to shoot a 65 and sit a shot behind Johnson and Burgoon.
Kevin Kisner (66), Kyle Stanley (68) and Camilo Villegas (70) are further back at 12 under.
Villegas dropped back into that tie for fifth after mixing three birdies with three bogeys.
Jason Day, who missed the cut at last week's Masters, continued his consistent showing with a second straight 67, the Australian sitting at nine under in a tie for 14th.