Schwartzel looked like doubling his advantage when he rolled in a seven foot birdie putt at the fourth, but Bourdy followed him in from five feet.
Both players found the green in one at the driveable par four sixth and walked off with birdies, although Schwartzel may feel he should have done better after a magnificent three wood to six feet.
Schwartzel, who won by 11 shots on Sunday, was threatening to establish huge lead once more when he hit his tee shot to two feet at the seventh and rolled in a ten footer at the eighth to reach 18 under.
Bourdy was three behind on 15 under, with a further three shot gap back to Fichardt.
Elsewhere Keith Horne had a hole-in-one at the 12th for the second day running and as a result had advanced to ten under.