Portugal's Ricardo Santos carded a flawless 62 to claim the lead after a day of low scoring in the Africa Open in East London.
Santos, who was the European Tour rookie of the year in 2012 after winning his first title on home soil in the Madeira Islands Open, fired nine birdies and no bogeys to finish nine under par.
He sits two ahead of Garth Mulroy, Rhys Davies, Richard Bland and Lucas Bjerregaard.
Among those to shoot in the 60s were the Irish trio of Damien McGrane, who carded a four-under 67 putting the Meath man a shot ahead of Michael Hoey (68), and rookie Kevin Phelan (69), while David Higgins finished with a 70 and Gareth Maybin finished level after a 71.
"I played really solidly today and gave myself a lot of chances for birdie, and I took a lot of those chances," Santos said. "I'm very pleased to make a run like I did today.
"I hit the ball solidly from the tee and my putting was all good. To shoot minus nine you have to play awesome golf, so I'm really pleased with every piece of my game.
"If the wind blows this is a very tough course, but today if you put the ball in the fairway you had the chance to shoot a low round.
"Today was definitely one of my best rounds of golf so far. I put the ball very close, didn't miss a fairway, and that's the key on this course."
Mulroy was leading the South African contingent out to maintain their remarkable dominance of events on home soil.
George Coetzee's victory in the Joburg Open on Sunday means nine of the last 12 European Tour events staged in South Africa have been won by home players, with all four previous Africa Opens won by South Africans.