The Englishman got to grips with the hard and fast conditions at the Gary Player Country Club to fire a six-under 66 and earn a two-stroke advantage in the 30-player tournament.
After an early birdie at the long second, Fisher ignited his challenge with a superb run of four birdies in five holes from the sixth that propelled him to the top of the leaderboard.
The world No 88 jumped further clear with two more birdies at 14 and 15 before blotting his card with a bogey at the short 16th.
But he parred in to earn a comfortable lead in the clubhouse which was under threat from George Coetzee until the South African, who birdied the first three holes, made his only mistake of the day at the 18th to close on four under.
“I felt like I played pretty solid, I hit some real good shots. It’s funny listening to how people approach this golf course, some are aggressive, some play the opposite,” said Fisher afterwards.
“I didn’t miss too many fairways and played exactly how I wanted to. One bogey, seven birdies for six-under on this golf course…I’ll definitely take that and run.
“I hit one loose shot on the 16th and made bogey, but you can’t be too disappointed with one bad shot in 18 holes.”
Coetzee was joined in a share of second by Marcel Siem, who made five birdies in six holes around the turn and then won a brand new Volvo when his approach to the 17th green took a fortunate bounce off the fringe and rolled straight into the middle of the cup for an unlikely eagle.
The German, who announced afterwards that he would give the car to his mother, said: “It’s not the best golf shot at all for me in my career. I tried to draw it in and it stayed straight and hit the fringe and had a firm bounce to the left. It was really cool to hole that one.”
In-form Frenchman Alexander Levy kept a bogey off his card as he matched the 68s of Coetzee and Siem, while Ryder Cup star Stephen Gallacher failed to build on birdies at the first two holes as he settled for a 70.
Major champions and home favourites Charl Schwartzel and Louis Oosthuizen were also two under for the day along with compatriot Tim Clark, Miguel Angel Jimenez and Turkish Airlines Open winner Brooks Koepka.
Luke Donald???s bid to end a frustrating year on a high looked unlikely when he dropped three shots in four holes early on, but the former world No 1 responded with three birdies after the turn to salvage a 71.
Lee Westwood (72) ruined an excellent inward half with an ugly double-bogey six at the 17th, while US Open champion Martin Kaymer ??? the highest ranked player in the field ??? looked jaded as he laboured to a two-over 74.
Ryder Cup star Jamie Donaldson was going along nicely at two under before he dropped four shots over the final four holes, and Thomas Bjorn???s hopes of retaining his title look ultra slim as he sits at the foot of the leaderboard after failing to break 80.