Kaymer carded three birdies against just one bogey at the Gary Player Country Club, which continues to provide a stern test for the 12-man field. At 5-under 211, Kaymer leads by one shot over Louis Oosthuizen, who hopes to cap his 2012 season with a win in his home country.
Another South African with a major title to his name, Charl Schwartzel, sits behind Oosthuizen in third place, two shots off the lead after matching Kaymer's 2-under 70 on Saturday. A tie for fourth place at 2-under 214 includes the lone American in the field, Bill Haas, along with two-time defending champion Lee Westwood.
After holding the lead after 36 holes, Paul Lawrie struggled to a 3-over 75 Saturday to fall into sixth position, four shots off the pace. The Scotsman began with three bogeys on his first five holes in Sun City and was unable to get his round back on track.
A day after a 7-over 79 sent his name down the leaderboard, world No. 4 Justin Rose improved by 10 shots Saturday, firing a 3-under 69 to match Oosthuizen for the low round of the day. Rose will start the final round in a tie for eighth alongside Francesco Molinari and Carl Pettersson at 5-over 221, 10 shots behind Kaymer.