PRETORIA, 14 Mar 2015 (AFP) - South Africans Wallie Coetsee, George Coetzee and Trevor Fisher junior, Englishman David Horsey and overnight leader Spaniard Adrian Otaegui also have nine-under 201 totals.
And with 15 other title contenders within three strokes of the leading pack, the stage is set for a thrilling final round Sunday at Pretoria Country Club.
Lee collected three birdies on each nine, but two front-nine bogeys cost him the outright lead as he hunts a first European Tour triumph.
"I’m delighted," said twice runner-up Lee.
"This is a course where you can go quite low, as guys have done, but it does not take much to be offline and then you really get punished around here.
"Four under today was a great score. I’m still making a couple of silly mistakes, but I’m generally delighted with my game.
"It is consistently getting better and I am almost in a position where I’m completely happy with it."
Fisher, winner of the Africa Open in East London last weekend, recovered from four bogeys in five holes on the outward trek by picking up five birdies to finish with a 69.
Horsey, a three-time European Tour champion, also returned a 69 and Coetsee and Coetzee fared slightly better with a 68 each.
Otaegui, a 22-year-old seeking a maiden European victory, followed up his sizzling second-round 62 with a 72 over the 6,458-metre (7,063-yard) layout.
A two birdie-two bogey front nine was followed by three bogeys and just one birdie on the inward journey.
Recently appointed 2016 Europe Ryder Cup captain Darren Clarke carded a 68 for a 206 total and a low final round could bring the Northern Irishman into contention.
But the two previous Tshwane Open winners, defending champion Ross Fisher and Dawie van der Walt, have probably got too much ground to make up.
South African Van der Walt (72) is seven shots adrift of the leaders and Englishman Fisher (74) nine off the pace.
Leading Tshwane Open third-round scores Saturday at the par-70, 6,458-metre (7,063-yard) Pretoria Country Club (RSA unless noted):
201 - Wallie Coetsee 64-69-68, George Coetzee 67-66-68, Trevor Fisher jnr, 66-66-69, David Horsey (ENG) 63-69-69, Craig Lee (SCO) 67-68-66, Adrian Otaegui (ESP) 67-62-72
202 - Ockie Strydom 66-69-67, Erik van Rooyen 66-69-67,
203 - Raphael Jacquelin (FRA) 65-70-68, Morten Orum Madsen (DEN) 63-72-68, Edoardo Molinari (ITA) 66-66-71
204 - Dean Burmester 65-68-71, Mikael Lundberg (SWE) 70-68-66, Tjaart van der Walt 69-69-66, Justin Walters 66-71-67
205 - Felipe Aguilar (CHI) 68-69-68, Richard McEvoy (ENG) 70-66-69, Keith Horne 65-67-73, Moritz Lampert (GER) 68-70-67, Eduardo de la Riva (ESP) 71-68-66, Robert Rock (ENG) 69-70-66