Felipe Aguilar turned in 30 to open up a one-shot lead early on day two of the Tshwane Open at Pretoria Country Club.
The Chilean lost his card last season but regained it at the Qualifying School to make it 11 uninterrupted campaigns on the European Tour, although he did miss his first three cuts in 2018.
An opening 65 on Thursday hinted at a return to form and three birdies and an eagle in round two confrmed that and moved him to 11 under, a shot clear of home favourtie George Coetzee.
The 2015 champion was also making a big move, picking up six shots in his first nine holes to get to double figures.
Mikko Korhonen, a runner-up here last season, was then at eight under.
Aguilar picked up birdies on the third, fifth and seventh before eagling the par five ninth, while Coetzee - who started on the tenth - made four gains in a row from the 12th and added to them on the 17th and 18th.
Finn Korhonen had birdies on the 12th, 13th, 14th, 16th and 18th and, while he dropped a shot on the first, he regained it at the third.
Overnight leader Louis de Jager was among the late starters at seven under, as were the players at six under - South African Thomas Aiken and American Julian Suri.
Frenchman Julien Guerrier, Scotland's Scott Jamieson and South African Breyten Meyer had all moved into the group six shots off the lead.
