The Open champion, four ahead at the start of the day, ensured no-one got near him by firing a blistering 63, a new course record.

Colin Montgomerie, his closest challenger, picked up five shots with a 67 but still could not get close to his old rival.

Such was Els' dominance in the tournament that he did not drop a single shot after the 13th hole of his second round.

He finished his final round with three straight threes to come home in 30, ending in style by chipping in at the last.

"That was probably the round of my life," a delighted Els said after collecting a cool $2m (�1.35m) - the biggest winner's cheque in golf.

"I don't think I've ever gone into the final round of a tournament leading and shot a 63."

It was Els' third victory in the lucrative Sun City event in the past four years, and his most decisive yet after a superb putting display.

"I was really playing well coming in and I was making a lot of putts," he added.

"You get into that zone and the hole looked pretty big to me today. It was great."

American Chris DiMarco finished third, ahead of compatriot Jim Furyk and Retief Goosen, who delighted the home crowd by holing his approach shot on the last for an improbable three.

Final Scoreboard:

-21 Ernie Els (Rsa)
-13 Colin Montgomerie (Sco)
-10 Chris DiMarco (USA)
-7 Jim Furyk (USA), Retief Goosen (RSa)
-5 Sergio Garcia (Spa)
-4 Nick Price (Zim)
-3 Darren Clarke (NIrl), Bob Estes (USA), Robert Allenby (Aus)
Par Padraig Harrington (Ire)
+ 1 Michael Campbell (Nzl) (78)