Els finished at 29-under-par 259 and established a new European Tour record for lowest score in relation to par. The former record of 27-under par belonged to Jerry Anderson when he turned the trick at the 1984 Ebel European Masters-Swiss Open. John Daly equaled the score in 2001 at the BMW International.
The reigning British Open champion nearly matched the European Tour record for low aggregate score but missed David Llewellyn and Ian Woosnam's record by a single stroke.
Els smashed Tiger Woods' tournament record from 2001 by four shots as the South African earned his fourth victory worldwide in 2003.
He opened the season by setting the PGA Tour's record for lowest score in relation to par at the Mercedes Championships. Els finished that tournament at 31-under par and followed the next week with a playoff victory over Aaron Baddeley at the Sony Open in Hawaii.
Els came to Singapore the week after the Sony Open and lost by a single stroke before successfully defending his title the following week at the Heineken Classic.
All totaled, Els now has won four of five starts in 2003, five of his last six dating back to last year's Nedbank Challenge and is first on both the PGA Tour money list and the European Tour Order of Merit.
'The way I'm playing now is some of the best golf I've ever played,' said Els, who captured this title in 1997. 'The whole package is pretty good at the moment.'
Stephen Leaney and Andre Stolz, both from Australia, shot matching rounds of 6-under 66 to finish tied for second place at 19-under par but neither got within seven shots of Els' lead on Sunday.
Els, who began the round with a nine-shot advantage, looked shaky to start the round as his second nearly found the water at the par-5 third. He took off his shoes and socks and chipped the ball into a greenside bunker, where his blast left him 15 feet to save par. Els rolled home the putt to answer any doubts that this tournament was his.
He hit a spectacular approach at the fourth that left him inches from the cup. He tapped that putt in for birdie then holed a seven-footer for birdie at the eighth to grab a nine-shot lead.
The Big Easy stumbled at the ninth when his second landed in a bunker. He played his third seven feet from the hole but missed the par-saving putt. That would be the last mistake of the round for Els.
He holed a seven-foot birdie putt at the 10th, two-putted for birdie from the fringe at No. 11 and sank a 30-footer for birdie at the 12th to reach 27-under par and take a nine-stroke advantage.
Els parred the 13th and caught a break at the short 14th. His tee ball bounced off a tree and left him with an open shot to the green, where he played his ball to 12 feet. Els made that putt and birdied the 15th to claim a 10-shot edge.
He had a chance for another birdie at No. 17 when his putt from the fringe hung on the hole but did not fall. Els parred the 18th to cap off his amazing week.
'This week everything went right,' he said. 'I had a great time. The greens are soft, the wind stayed away all week and I could just go out there and attack the golf course.'
Retief Goosen, the 2002 champion, tied for fourth with Robert Allenby, Justin Rose, David Smail and Jean-Francois Remesy. The group came in at 17-under-par 271.
Niclas Fasth and Craig Kamps shared ninth at minus-16.