South African Richard Sterne and German Maximilian Kieffer shared the lead on 63 after the first round of the Joburg Open at the Royal Johannesburg and Kensington Golf Club here on Thursday.
The pair are two strokes ahead of South Africans MJ Daffue, Bryce Easton and Tyrone Mordt as well as Sweden's Joakim Lagergren and American Peter Uihlein in an event co-sanctioned by the European Tour and local Sunshine Tour.
David Horsey of England, Frenchman Alexandre Kaleka, Espen Kofstad of Norway and Brazilian Adilson da Silva are among a dozen golfers a further shot back on 66 after an opening round staged in clear, hot South African summer conditions.
Pre-tournament favourite and 2011 US Masters champion Charl Schwartzel of South Africa began with a 68, while compatriot and defending champion Branden Grace would have expected to do better than a 72 after the first 18 holes.
Sterne started his round superbly with three consecutive birdies, followed by another on eight and an eagle on nine where a driver and a four-iron brought him to the edge of the green and his deft chip dropped into the hole.
The hot streak cooled somewhat on the back nine with Sterne adding two birdies to maintain a trend of good starts having opened with a 62 at the Dubai Desert Classic last week, where he came second to Scotland's Stephen Gallacher.
Tour rookie Kieffer was a model of consistency, rattling off five birdies on the front nine and a further three on the inward journey while not dropping a single stroke.
Each competitor in the 210-strong field chasing a 206,050-euro (S278,744) first prize, plays one round over the west course and one over the longer, more challenging east course, where the final two rounds will be staged.