A flawless round on Saturday moved Louis Oosthuizen into pole position to win the South African open

Louis Oosthuizen is primed to claim back-to-back South African Open titles on home soil after taking a one-shot lead in Johannesburg on Saturday.

Defending champion and home favourite Oosthuizen went into the third round at Randpark Golf Club three shots off the pace but carded a bogey-free seven-under 64 on the Firethorn Course to hit the front on 15 under.

The 2010 Open Championship winner scrambled magnificently, playing some magnificent shots amid the rough and trees, to remain ahead of Marcus Armitage.

Armitage surged into contention after a pair of eagles in a brilliant 62, with only a bogey at the last denying him a share of the lead.

Jaco Ahlers is a shot back in third, with 18-year-old South Africa amateur Jayden Trey Schaper among a five-man group on 12 under.

Overnight leader Tapio Pulkkanen fell five shots off the pace set by the impressive Oosthuizen.