Thomas Aiken produced a magnificent 11 under par round of 61 to take control of the Alfred Dunhill Championship during the third round.
The South African eagled the 18th at Leopard Creek Golf Club in his native country to move three shots clear of American Len Mattiace at 18 under par.
The 2003 US Masters runner-up Mattiace was four under for the day at 15 under par after 12 holes, a shot clear of fellow overnight leader Oskar Henningsson, England`s David Lynn and Aiken`s compatriot Richard Sterne.
Lynn was six under for his round after 16 holes, while Henningsson and Sterne both had five holes to play in their third round.
Aiken`s round put him on course to be the first home winner of the event since Ernie Els three years ago and beat Dean Robertson's record of 62 for the lowest round in the event's history.
The 25 year old`s rise to the top of the leaderboard is all the more impressive since he started the tournament with a double bogey six at the first and was seven strokes off the pace following his opening round 72.