Midlander Rock is ranked 449th in the world

England's Robert Rock held a one-shot lead after a windy first round of the South African Airways Open in Paarl.

Rock, 30, defied the tough conditions to shoot a two-under 70 to edge the home trio of Alex Haindl, Charl Schwartzel and Ulrich Van den Berg.

Darren Clarke was in a large group at level par, while Retief Goosen was two over and Greg Norman ended three over.

Ernie Els, who blew last week's Alfred Dunhill event with a triple-bogey eight on the 18th, carded 77 for five over.

If you hit a bad shot here you get punished Robert Rock

The Wentworth-based South African, the world number five, was joined in a tie for 49th place by England's 2008 Order of Merit leader Ross Fisher.

US Open champion Angel Cabrera signed for an 80, while Northern Ireland's Rory McIlroy, who turned pro this year after an impressive Open as an amateur, amassed an 11-over 83.

Rock, the world number 449, shot five birdies and two bogeys to edge ahead of the field.

"Even at 0700 it was blowing pretty hard. I had 29 putts and hit 10 fairways, so overall I was striking the ball well and holing crucial putts to save par and make birdies," he said.

"All my bogeys were not the fault of the wind, they were my own mistakes. I hit good shots and gave myself chances, but I also messed up quite a fair bit. If you hit a bad shot here you get punished."

Two-time winner Trevor Immelman withdrew after two holes with a rib problem which caused him trouble with breathing.

It was later revealed that he had a lesion on the 11th right rib, which will be surgically removed next Tuesday, ruling him out for up to six weeks.