Rookie Austin Cook will take a three-shot lead over Chris Kirk into the final round of the RSM Classic as he chases a maiden PGA Tour title in only his 14th event.
The 26-year-old began the day with a one-shot lead but surged clear with a four-under-par 66 at Sea Island in Georgia.
Cook birdied the first and second after excellent approach work and made further gains at the seventh and ninth to turn in 31.
His only blemish of the day came with a bogey on the 14th after a wayward drive was followed by a three-putt, but Cook responded with a birdied from four feet at the next.
American Cook sits 18 under par with a round to play, three clear of compatriot Kirk (64), with Brian Gay (69) a shot further back in third.
Scotland's Russell Knox is the leading British contender after a round of 68 left him seven under.
Ireland’s three-time major winner Pádraig Harrington could only manage a 74 which left him down in 72nd on level par for the tournament.
