JOHANNESBURG, Feb 8, 2013 (AFP) - Tied with fellow South African Richard Sterne, who shot 65, Fisher lead countryman George Coetzee by three strokes. South Africans Keith Horne and Charl Schwartzel, as well as Chilean Felipe Aguilar, are five behind.
The 33-year-old Fisher had good rhythm from the start with an eagle on the par-five second, followed by birdies on the third and ninth, and five more on the inward nine.
"It was a great day out there. Everything just happened for me and I sank the putts I needed to sink. I was happy and patient with myself -- walked slow and did everything slow -- and it was just a good day," he said afterwards.
He was cautiously proud of the lowest round ever at the Joburg Open, co-sanctioned by the European Tour and the local Sunshine Tour.
"It's nice to have the record. But I'm going to focus on my game and not worry about what everyone else is doing. It's just a number -- I've got to go out there and still try to make birdies," said the 2012 Sunshine Tour Players' Player of the Year.
Sterne held onto his overnight lead with a second bogey-free round in a row, staying in the run for a win after a close second at the Omega Dubai Desert Classic last week.
"You would like to stay up there and give yourself a chance come Sunday, but it's not so easy being up there from day one," said the 31-year-old.
"You've got guys there who've won a few tournaments and obviously Charl (Schwartzel) is there. And George Coetzee - he hasn't won, but he's due. It's a long way from over -- we're only halfway," he said.
Each competitor in the 210-strong field chasing a 206,050-euro ($278,744) 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.
Leading scores after the second round of Joburg Open over par-71, 6618-metre, west course and par-72, 6942-metre, east course at Royal Johannesburg and Kensington Golf Club Friday (RSA unless stated):
128 - Trevor Fisher 66-62, Richard Sterne 63-65
131 - George Coetzee 67-64
133 - Felipe Aguilar (CHI) 67-66, Keith Horne 67-66, Charl Schwartzel 68-65
134 - Tommy Fleetwood (ENG) 68-66, Jose Manuel Lara (ESP) 69-65, Peter Uihlein (USA) 65-69, Jaco van Zyl 66-68
135 - Dean Burmester 67-68, MJ Daffue 65-70, David Drysdale (SCO) 68-67, Bryce Easton 65-70, Richard Finch (ENG) 67-68, Lorenzo Gagli (ITA) 67-68, Maximilian Kieffer (GER) 63-72, Tyrone Mordt 65-70, Ricardo Santos (POR) 70-65
Note: Competitors play one round each over the west and east courses and the final two rounds over the east course