Justin Thomas regained control at The CJ Cup at Nine Bridges, holding a share of a two-stroke lead with Scott Brown after Saturday's third round.
Coming off a disappointing 74, Thomas carded a two-under 70 to move into nine under in Jeju, South Korea.
Thomas, the FedEx Cup and US PGA Championship winner, mixed five birdies with a bogey and a double bogey.
His American countryman Brown joined him atop the leaderboard after shooting a 71, completed with a final-hole birdie.
Brown recovered late in his round, birdieing the 15th and the 18th holes, the latter after a brilliant approach.
Swirly winds again troubled players at the first PGA Tour event to be played in South Korea.
Anirban Lahiri (69) and Marc Leishman (71) are tied for third at seven under, a shot ahead of Whee Kim (72), Cameron Smith (73) and Lucas Glover (74).
Overnight leader Luke List fell into a tie for eighth after struggling to a four-over 76.
The best round of the day came from local An Byeong-hun, who carded a 67 to join List at five under.
The conditions are expected to be trickier on Sunday, with Thomas eyeing his fifth PGA Tour win of 2017.
