Jamie Donaldson raced into a three-shot lead of the Nedbank Golf Challenge with a six-under-par 66 at Sun City.
After the 30-man field finished their opening rounds following Thursday's rain, the Welshman was only a shot behind leader Sergio Garcia, but Donaldson soon stamped his authority on the second round.
Three birdies in the opening four holes lifted him into the lead, and a further two on the final holes of the back nine saw him reach the turn in 31.
A bogey at 10 was the only blemish on his card as he added another two birdies at 13 and 14 to complete a successful round.
"I've played very nicely for the first two rounds and hit a lot of good shots so I am happy with the way I am playing," he said after moving to the top of the leaderboard.
"We had to play six holes of the first round and then back out after a 45-minute break for the second, so it's been a long day."
The 38-year-old leads on 11-under par going into the weekend with Henrik Stenson and Ryan Moore leading the charge in a tie for second.
Thomas Bjorn and Martin Kaymer sit a further shot back – the latter matching Donaldson's score for the second round to climb into contention.
Garcia could not reproduce his opening-round 66 as he carded a one-over 73 to drop back to a tie for ninth.
Race to Dubai leader Charl Schwartzel is joined by Brendon De Jonge and DA Points in a three-way tie for sixth place, five shots behind Donaldson on six under.
The lone Australian in the field, Peter Senior, recovered from his disastrous 80 in the opening round to post a respectable 68 and move up to 29th position at four over.