Wang Jeunghun holds a three-shot lead going into the final day of the Nedbank Golf Challenge after carding a superb eight-under-par 64 in the third round on Saturday.
Sweden's Alex Noren had led the way after 36 holes in Sun City, South Africa, with Wang five strokes off the pace on three under.
But the tables turned in emphatic fashion on day three as Wang produced a flawless effort to surge up the leaderboard and Noren struggled to a three-over round of 75 to drop down to level fourth.
Louis Oosthuizen is Wang's closest challenger on eight under. Andy Sullivan is third on seven under, two strokes ahead of Noren.
Henrik Stenson can win the European Tour's Race to Dubai for a second time with victory at the Gary Player Country Club, but he Open champion is seven shots adrift despite matching his first-round three-under 69.
Jaco van Zyl is tied with Stenson in sixth, a shot behind Noren and Branden Grace.
The day, though, belonged to Wang, who birdied four of the first six holes and made the turn in 32 strokes.
Wang came within a few feet of an albatross at the par-five 10th and was still able to tap in for an eagle, which he duly followed up with his fifth birdie of the day at the 11th.
Looking for his third win of 2016, Wang finished with a flourish by knocking in an 18-foot putt on the last, leaving Oosthuizen with plenty of work to do to catch the 21-year-old South Korean.
Very impressive.-- The European Tour (@EuropeanTour) November 12, 2016
Wang birdies 18, signs for a 64. pic.twitter.com/UOBUUVYSbg
The 2010 Open champion turned at level par, but had a share of the lead at 10 under after birdies on 10, 13, 15 and 16, only for that effort to be undermined by successive bogeys on the final two holes.