Robert Rock took full advantage of an early start times on day two of the Joburg Open to post a challenging 11 under par clubhouse score.
With overnight leaders Jamie Elson and Damien McGrane among the later starters, Rock made his presence felt on the leaderboard at Royal Johannesburg and Kensington Golf Club.
After a four hour delay due to thunderstorms on the opening day, the Englishman had to finish his first round on returning to the course.
Finishing the tougher East Course first, Rock birdied the last two for a 65 – a joint-best effort on the more difficult layout.
Two-time Sunshine Tour winner Jbe Kruger added a 66 on the West Course to move to ten under, but Italian Open champion Rock went one better after mixing four birdies, two bogeys and an eagle three at the second in a 67.
At 11 under he led by one from Kruger and another South African, Brendan Grace, who bogeyed the final hole of the West Course for a 66.
