Carl Pettersson will take a one-shot lead going into the final day of the RBC Heritage in North Carolina.
The Swede hit five consecutive birdies on the front nine of the Harbour Town Golf Links before another saved shot on the final hole put him on 12-under-par.
American Carl Knost is a shot further back following his round of 70, while fellow countryman Zach Johnson is on eight-under.
England's Luke Donald, who needs to finish inside the top eight to retain his world number one ranking, posted a round of 71 to leave him two-over.
