Justin Thomas holds a a two-stroke lead at the halfway stage of the CJ Cup in South Korea after a bogey-free-nine-under-par 63 propelled him to the top of the leaderboard.
Starting the day with four successive birdies, and finishing with nine in total, including one at the last, he moved himself up eight positions on the leaderboard at 13 under through 36 holes.
Thomas leads home favourite An Byeong-hun (69) and New Zealander Danny Lee (66) - the two tied for second - heading into the third round at the Nine Bridges Golf Club on Jeju Island.
An had been the leader after the second round but two bogeys and five birdies dropped the South Korean back while Lee improved to 11 under but he could have been a stroke better off had it not been for a bogey on the 18th.
Former world number one Jordan Speith (65) was also a big mover, climbing 25 positions, thanks in part to back-to-back birdies to end the day, to sit four shots off the pace ahead of Saturday's penultimate round.
Defending champion Brooks Koepka had a day to forget, shooting a three-over-par 75, including five bogeys, to leave him even par.
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