Sun City - South Africa's Zander Lombard stormed into the lead with a seven-under-par 65 in the second round of the Nedbank Golf Challenge at the Gary Player Country Club on Friday.
The powerfully-built 24-year-old from Pretoria, with a two-round total of 11-under-par 133, surged past fellow countryman Louis Oosthuizen, who was unable to repeat the heroics of his first-round 63.
Oosthuizen trailed Lombard by two shots after a making three birdies and three bogeys in an even-par round of 72.
Belgium's Thomas Detry was third, two strokes further adrift, after an adventurous round of 71 which included five penalty shots.
Tommy Fleetwood of England and Marcus Kinhult of Sweden shared fourth place on six-under, both making second successive 69s.
"It's a tough course," said Fleetwood.
"Anything can happen."
Lombard dropped a shot on the first hole but then played flawless golf, making six birdies and an eagle on the par-five 10th when he holed a putt from the fringe.
"The nerves were out there the first few holes but I settled in quite quickly," he said.
"My caddie and I tried to make birdie on every hole. It was my mindset, really positive."
Lombard started the week in 76th place on the European Tour's Race to Dubai and was an outsider to qualify for next week's Tour championship in Dubai, which is reserved for the top 50 players on the order of merit.
But if he can hold on and win the $2.5-million first prize he will leap to 13th in the standings.
"I'm trying not to think about that," said Lombard of the possibility of a huge payday. But he said he was keen to qualify for Dubai.
"It's the pinnacle of the year and you want to play it."
Detry briefly held the lead at 10-under par when he birdied the par-three 12th hole.
He earlier had to take three off the tee on the third hole when he drove the ball deep into bushes and took a penalty drop after another wayward drive on the eighth. He escaped with bogey on both occasions.
But a third errant drive on 17 proved more costly.
The tee shot requires a long carry over water and Detry pulled his drive into the lake and needed to play three off the tee for the second time in his round.
It could have been five off the tee but his second drive, which was seemingly headed for more disaster, hit a windsock pole on the edge of the water and bounced into play. He made a double-bogey six.
Detry made five birdies and an eagle but had four bogeys and a double bogey.
While Lombard was scorching around the longest course on the European Tour, there were struggles for his playing partners, defending champion Lee Westwood and home favourite Ernie Els.
The two veterans, who started the day alongside Lombard in joint fourth place, both dropped down the leaderboard.
Westwood dropped shots on both the par-fives on the first nine and struggled to a one-over 73, while Els had a nightmare stretch, dropping seven shots in four holes from the fourth, twice driving into thick bush as well as duffing a chip and missing a short putt.
He took 43 shots to the turn on the way to a nine-over-par 81.
Kalle Samooja of Sweden made an albatross two on the par-five 10th, his first hole of the day. It was the fifth albatross of the season on the European Tour, achieved with a four-iron from 235 yards.
He briefly appeared on the leaderboard, making 31 on his first nine but faded with 40 on the second nine for a 71.
Leading scores after the second round of the European Tour's Nedbank Golf Challenge on Friday at the par-72 Gary Player Country Club in Sun City (RSA unless noted):
133 - Zander Lombard 68-65
135 - Louis Oosthuizen 63-72
137 - Thomas Detry (BEL) 66-71
138 - Tommy Fleetwood (ENG) 69-69, Marcus Kinhult (SWE) 69-69
139 - Joachim B Hansen (DEN) 69-70, Aaron Rai (ENG) 70-69, Jason Scrivener (AUS) 69-70
140 - Nacho Elvira (ESP) 70-70, Matthew Fitzpatrick (ENG) 71-69, Mikko Korhonen (FIN) 70-70, Guido Migliozzi (ITA) 67-73, Alvaro Quiros (ESP) 70-70, Paul Waring (ENG) 69-71, Bernd Wiesberger (AUT) 71-69