Chris DiMarco joined overnight leaders Kenny Perry and Vijay Singh at the top of the leaderboard on the second day of the Nedbank Challenge at Sun City.
DiMarco began on Friday by picking up two more shots to move to eight under par.
Australia's Stephen Leaney also made an early charge, picking up three birdies to move to within one shot of the lead.
Ernie Els continued to struggle for form however. The South African birdied the opening hole but then bogeyed two and three.
Sergio Garcia and Padraig Harrington were holding steady at their overnight scores of two under and level par respectively, some way off the pace.