Johannesburg, South Africa (Sports Network) - Charl Schwartzel gutted out a four-under 67 in difficult conditions Sunday to successfully defend his title at the Joburg Open.

Schwartzel finished the tournament at 19-under 265 and won by four strokes at the East Course at Royal Johannesburg and Kensington Golf Club.

The victory was Schwartzel's sixth on the European Tour.

Garth Mulroy, a third-round co-leader with Schwartzel and Thomas Aiken, managed only an even-par 71 in rainy conditions. He took second at 15-under 269.

Aiken struggled to a one-over 72 and came in third at minus-14. Jamie Elson's even-par 71 was enough to give him fourth at 13-under 271.

In damp, demanding conditions on Sunday, Schwartzel pulled away from his fellow co-leaders early. He birdied the first and third holes, but a bogey at the fourth dropped him down to 16-under par.

Schwartzel was still in the lead due to the fact that Mulroy and Aiken parred their first four holes. Aiken ran home a five-footer for birdie at the fifth, but Schwartzel birdied No. 6 to move back in front by a stroke.

A Schwartzel birdie at the par-five eighth inched him two ahead, but a poor approach at the ninth led the South African to a bogey.

"I hit that second shot a little strong there," said Schwartzel of his second at the par-four ninth, "and that wasn't a good bogey for me."

Not much went well for Schwartzel on the back nine. He hit only one fairway and sprayed some of his iron shots all over the course as well. He landed in a bunker at the par-three 13th, but holed the bunker shot. Schwartzel was three clear and that would be all he needed.

"Garth and Thomas probably outplayed me on the back nine," admitted Schwartzel, "but I managed to get a few more putts in the hole."

He found more trouble at the par-five last when his approach sailed right. He was forced to chip out with his second, but his third nearly went in the hole twice.

Schwartzel's approach nearly found the cup on its second bounce, then nearly spun in a second time. Although he failed to make the unlikely eagle, Schwartzel sank a six-footer for birdie to pad his margin of victory.

"I had to really dig deep there on the back nine and managed to make a score," acknowledged Schwartzel. "I'm really pleased that all my hard work has paid off."

Jean-Baptiste Gonnet shot a one-over 72 and finished fifth at 12-under 272. Scott Jamieson fired a six-under 65 on Sunday and that was good for sixth at minus-11.

Tjaart van der Walt (67), George Coetzee (69), James Kingston (71), Allan Versfeld (72) and Oscar Floren (72) tied for seventh place at 10-under-par 274.

NOTES: Schwartzel moved to the top of the European Tour Race to Dubai with the victory...He joined Ernie Els and Trevor Immelman as South Africans to successfully defend a title on the European Tour...Mulroy lost a playoff at this event in 2008...Next week is the Dhabi HSBC Golf Championship, where Germany's Martin Kaymer captured last year's event.