Paul Waring led by one shot after 12 holes of his second round when play was suspended for bad light at the Joburg Open on Friday.
The Englishman made five birdies in those holes on the West Course at Royal Johannesburg and Kensington to move 12 under par, ahead of South Africans Darren Fichardt and Dean Burmester.
Fichardt was in the clubhouse with a second 66, thanks mainly to a sizzling opening nine on the East Course. Fichardt picked up six shots in those nine holes with four birdies and an eagle. Burmester was 11 under with three holes of his second round to complete.
Organizers have been playing catch-up since rain led to a waterlogged course on Thursday, forcing 98 players to finish their first rounds on Friday morning.
Fichardt was one of those, playing the last six holes of his opening round on the West Course before dashing across to the East Course to play his second round.
He was the clubhouse leader before Waring, who opened with a 65, made a run of three straight birdies to push ahead before the light faded.
Jacques Kruyswijk is fourth on 10 under and defending champion Haydn Porteous part of a five-way tie for fifth a shot further back.