Scotland's Scott Jamieson shot a second round 64 at the Volvo Golf Champions in Durban - the same city where he captured his first European Tour title only last month.
The 29 year old's nine-birdie display lifted him to 11 under par at halfway and into a share of the lead with Thai Thongchai Jaidee and South African Louis Oosthuizen, who still had one hole to play.
Then came a five stroke gap to Irishman Shane Lowry, Scot Paul Lawrie, Dane Thomas Björn, France's Julien Quesne and England's Danny Willett.
Jamieson's maiden victory came in an event reduced to 36 holes because of bad weather - it qualified him for this week - and there was a two-hour delay for rain before play could resume today.
"If it continues to rain maybe that's a good thing for me," Jamieson said.
The field is only 33-strong and limited to last year's winners, previous holders of the title and those with ten or more career European Tour titles.