Martin Kaymer will take a one-stroke lead into the final round of the Nedbank Golf Challenge in Sun City after holding his nerve in testing conditions at the Gary Player Country Club today.

A windy, overcast day made for a low-scoring third round, but Kaymer tallied three birdies and just one bogey to post a two-under 70 and move to five under overall.

Kaymer, who began the day a shot behind overnight leader Paul Lawrie, was required to hold his nerve at the last to maintain the outright lead, the German sinking a tickly putt from around 10 feet to make par.

South Africa's Louis Oosthuizen went round in 69 to sit one off the lead, while compatriot Charl Schwartzel is in the mix in third place, two shots off Kaymer after a 70.

Lawrie suffered a trying day as the Scot carded a three-over 75 to drop back to sixth place, while England's defending two-time champion Lee Westwood (70) is in a share of fourth place on two under alongside America's Bill Haas.

Kaymer knows he is there to be shot at tomorrow with such a slender lead and some real quality in the chasing pack, and insists the only option is to go on the attack.

"I think a mistake would be if I try to defend my lead," he said on "You cannot approach the last round like that."

"I think tomorrow you just need to stay very patient and give yourself a shot with four to five holes to go" - Louis Oosthuizen

"You hit fairways and greens and that is the most important, then think you will have a few more chances to make birdie.

"You cannot play too aggressive at certain holes, but you must take your chances. That is my goal."

Oosthuizen is bidding to become the first South African winner of this event since 2007 and set five birdies against two bogeys today to give his chances of claiming the title a huge lift.

And he admits the final round will be all about staying in touch until the final holes with conditions forecast to remain difficult.

"I would not be surprised if it is seven under winning it tomorrow," he said.

"I think tomorrow you just need to stay very patient and give yourself a shot with four to five holes to go.

"It will be a great finish to a good season. I have played really well the whole season, one or two came really close to a few as well and I think winning it here would mean everything."