Tapio Pulkkanen carded a bogey-free 66 to take a one-shot advantage at the top of a congested South African Open leaderboard, but Australia's Maverick Antcliff remains in touch, three strokes off the lead.
Just three shots separate the first 22 players at the halfway point of the European Tour event, with Finland's Pulkkanen alone at the summit on 11 under par after he managed five birdies on a tougher scoring day for the 240-strong field.
Brisbane-based Antcliff, who earned his European Tour card for 2020 via the China Golf Tour, is in a group of 12 players sharing 11th place after carding a second successive 67 to sit on eight under.
Aussie compatriot Min Woo Lee is a shot back, tied for 23rd after a round of 69.
At one point there was a seven-way tie at the top of the leaderboard at the Randpark Golf Club. Pulkkanen is seeking a first win on tour, but will have to fight off a sizeable chasing pack if he is to be victorious in Johannesburg.
Englishman Sam Horsfield (68) is one of five players a shot back, in a group that includes home amateur Jayden Trey Schaper (67), and the South African trio of Thriston Lawrence (65), Jaco Ahlers (66) and Trevor Fisher Jnr (67).
American overnight leader Johannes Veerman could only manage a par 71 on Friday following his superb 62 in his opening round, and is two shots off the pace.
Former Briitish Open winner and defending champion Louis Oosthuizen (69) is alongside world No.231 Ancliff on eight under in a group looking to make a move at the weekend.