Paul Peterson saw his lead cut to a single shot when the weather-affected first round of the Joburg Open resumed at Royal Johannesburg and Kensington Golf Club on Friday.
Jacques Kruyswijk, who was one of 98 players still to complete their opening rounds when play was suspended due to a waterlogged course at 2.35pm on Thursday, fired an eagle and two birdies in his final six holes on Friday morning to move into second place.
More rain overnight caused further delays on Friday morning, but when play finally got back under way at 9.30am, Kruyswijk dragged himself into contention.
The South African, who was four under par after 12 holes when play was halted on Thursday, picked up his first shot of the day at the 14th before notching an eagle at the next to join English pair Aaron Rai and Paul Waring on seven under.
Kruyswijk added another birdie at the 17th before safely parring the last to sign for a bogey-free 63 and move within a shot of Peterson at the summit.
Peterson went out and came back in 31 on the West Course on Thursday to set an intimidating clubhouse target.
And with no-one able to match Peterson's nine-under-par 62 on Friday morning, the American remains in front heading into the second round.
Scotland's David Drysdale jumped up the leaderboard on Friday, closing his first round with gains at the 13th, 15th and 17th to join Rai and Waring in a share of third on seven under.
Anton Karlsson, George Coetzee and Adilson da Silva joined the large group on six under.
