JOHANNESBURG, November 22, 2013 (AFP) - Johannesburg native Schwartzel began as one of the late starters but fired five birdies and an eagle over the front nine to reach the turn at seven under before easing off down the back stretch.
A 36-hole total of 132, on the par-72 Glendower club layout at Ekurhuleni, drew him level with Crespi, who carded a five under 67 to go with his opening round of 65.
"It was just one of those nines where most things go right," said Schwartzel, who memorably won his only Major at Augusta in 2011.
"I holed some nice putts and played some great shots to turn in seven under. It looked like it could be a really low one at one stage.
"It's nice to turn in a low nine and get yourself quickly up the board. I got a bit derailed by a short putt on 10. It sort of put the brakes on a little bit. Who knows what I would have been on (now) if that went in?" the South African told the European Tour website.
Crespi, 35, who has only had his European Tour card seven days after finishing third at the Qualifying School at PGA Golf Catalunya last week, carded six birdies -- four of which came on the front nine -- and just the one bogey.
"I missed a lot of fairways and a lot of greens today. My long game was not how I like to play. My putting and chipping was pretty amazing," said Crespi.
"I was expecting a good tournament because I was playing well. Obviously not this big but I am pretty confident about the weekend. I'll just try to remain calm and play my game my way." he added.
One shot back in the first event of the 2014 Race to Dubai was Morten Orum Madsen, whose impressive six-under-par 66 left the Dane eleven under.
It would have been even better for Madsen but for a bogey four on the penultimate hole -- his only dropped shot of the day.
Christiaan Basson (68) was fourth on 10 under while his South African compatriot Jbe Kruger was nine under, alongside England's James Morrison.
Leading scores after the second round of the South African Open on Friday (GBR & IRL unless stated, par 72):
132 - Marco Crespi (ITA) 65-67, Charl Schwartzel (RSA) 67-65
133 - Morten Orum Madsen (DEN) 67-66
134 - Christiaan Basson (RSA) 66-68
135 - Jbe Kruger (RSA) 65-70, James Morrison 69-66
136 - Ulrich Van Den Berg (RSA) 70-66, Matthew Nixon 64-72, Alejandro Canizares (ESP) 69-67, Tom Lewis 68-68, James Kamte (RSA) 69-67
137 - Thomas Aiken (RSA) 70-67, Garth Mulroy (RSA) 70-67, Retief Goosen (RSA) 66-71, Andrea Pavan (ITA) 67-70, Daan Huizing (NED) 68-69, Trevor Fisher Jnr (RSA) 70-67, Neil Schietekat (RSA) 69-68
138 - Hennie Otto (RSA) 72-66, Danie Van Tonder (RSA) 68-70, Jean Hugo (RSA) 71-67, Alastair Forsyth 72-66, Atti Schwartzel (RSA) 67-71
139 - Peter Whiteford 71-68, Warren Abery (RSA) 68-71, Johan Carlsson (SWE) 69-70, Oliver Bekker (RSA) 70-69, Andy Sullivan 71-68, Merwe Bennie Van Der (RSA) 69-70, Allan Versfeld (RSA) 71-68, Christopher Doak 71-68, Thomas Levet (FRA) 69-70