Sun City: World number one Lee Westwood of England stretched his lead to five strokes after three rounds of the Sun City Challenge on Saturday.
The 37-year-old, who replaced American golf icon Tiger Woods at the top five weeks ago, had to settle for a one-under 71 at a sun-drenched 7162-metre Gary Player Country Club.
It was his poorest round this week in the five-million-dollar tournament known as the African Major, but closest challenger and fellow Englishman Ross Fisher failed to take advantage after starting the round three shots behind.
Fisher faltered badly after moving to within two shots of Westwood five holes from the finish and missed a birdie putt on the last to end one over on 73, level with South African Tim Clark in second place.
After failing to match par in the opening round, Clark has climbed steadily up the leaderboard and did not drop a shot during his third round despite struggling to match the distance of his rivals off the tee.
Spaniard Miguel Angel Jimenez made too many visits to bunkers on the back nine and a 71 left him alone in third place, six adrift of Westwood.
South African Ernie Els, Dane Anders Hansen and Irishman Padraig Harrington, the first-round leader, are next on 210 and virtually out of contention for the record 1.25-million-dollar first prize.
Defending champion Robert Allenby of Australia slumped to a one-over 73 after two rounds of 70 and only Englishman Justin Rose and reigning British Open champion Louis Oosthuizen of South Africa trail him.
But Fisher was the unhappiest golfer in the clubhouse at this north-west resort after closing the gap on Westwood to two and then dropping shots at 14, 15 and 17, where the leader went five clear despite a bogey five.
A wayward drive left into dense rough cost Fisher a one-shot penalty at 14, the longest hole on the course at 550 metres, where he also visited a bunker en route to a bogey six.
Westwood moved four clear when his playing partner failed to hole an uphill putt at 15 and Fisher knew it was not his day when he double-bogeyed 17 for the second time in three days.
The last hole brought no change of luck as Fisher missed a four-foot birdie putt, while Westwood parred despite being shorter off the tee at 18 and 15 feet from the pin with his second shot.