DURBAN, January 11, 2014 (AFP) - The Englishman, seeking his second win on the European Tour, produced four birdies and a lone bogey to move to a ten under par total of 206.
Breathing down his neck with a share of second on 207 were France's Victor Dubuisson and Dutchman Joost Luiten, with last year's winner Louis Oosthuizen two off the pace despite a triple bogey seven at the 16th.
Fleetwood, who opened his Tour account in the Johnnie Walker Championship at Gleneagles last year, was satisfied to be in the lead after a demanding day's play.
"I played four or five really good holes, but obviously the rest of it I struggled," the 22-year-old told www.europeantour.com.
"You miss your tee shots you're always going to struggle for pars. I made one bogey but it was always coming at some point so I was quite cool and calm at the end of it.
"Three under around this golf course when you're not on your game is an absolutely brilliant score, and so I think it's showing I'm maturing as a golfer."
He is hoping a win in Durban can set him up for an "exceptional" year leading to a place in Paul McGinley's Ryder Cup team.
Dubuisson, third on the European Ryder Cup points list, had his short game to thank for a solid third round.
Local hope Oosthuizen meanwhile was leading the pack with three holes to go before his triple bogey slip-up after striking his second into deep undergrowth and declaring it unplayable.
"It's frustrating that I finally got my seven birdies, which you need to do around this course, but made too many bogeys," the 2010 Open Champion said.
"I was not great off the tee and hit a few wayward shots but I'm still happy to be right in there."
Fellow South African Braden Grace is a shot further back on seven under with Wales' Jamie Donaldson another stroke away alongside France's Raphael Jacquelin.
Scores after the third round of the $4 million (2.94m euros) Volvo Golf Champions event on Saturday at the Durban Country Club (GBR & IRL unless stated, par 72):
206 - Tommy Fleetwood 70 67 69
207 - Joost Luiten (NED) 70 67 70, Victor Dubuisson (FRA) 69 69 69
208 - Louis Oosthuizen (RSA) 68 69 71
209 - Branden Grace (RSA) 74 67 68
210 - Jamie Donaldson 71 71 68, Raphael Jacquelin (FRA) 67 73 70
211 - Brett Rumford (AUS) 73 70 68, Charl Schwartzel (RSA) 74 69 68
212 - Paul Casey 72 75 65, Chris Wood 70 71 71, Matteo Manassero (ITA) 72 67 73, Darren Clarke 69 71 72, Padraig Harrington 71 71 70
213 - Colin Montgomerie 70 74 69, Miguel Angel Jimenez (ESP) 76 70 67, Marcel Siem (GER) 70 71 72, Julien Quesne (FRA) 74 73 66
214 - Thomas Aiken (RSA) 72 72 70, Thomas Bjorn (DEN) 79 68 67, Morten Orum Madsen (DEN) 71 74 69
215 - Mikko Ilonen (FIN) 73 73 69 216
216 - David Howell 76 69 71
217 - Dawie Van Der Walt (RSA) 71 71 75, David Lynn 71 74 72, Jin Jeong (KOR) 73 76 68
218 - Peter Uihlein (USA) 70 78 70, Darren Fichardt (RSA) 73 71 74, Gonzalo Fdez-Castano (ESP) 74 73 71, Michael Hoey 72 73 73, Richard Sterne (RSA) 72 73 73
219 - Robert Karlsson (SWE) 74 72 73, Stephen Gallacher 73 74 72
220 - Kiradech Aphibarnrat (THA) 75 74 71 222 Simon Thornton 70 72 80
227 - Jose-Maria Olazabal (ESP) 73 77 77