Charl Schwartzel came under pressure from Darren Clarke at the start of the final round in the Joburg Open, before re-building his four shot lead.
Four clear overnight, the South African's advantage was halved when he bogeyed the third and Clarke birdied the next.
But there was a potentially crucial back in Schwartzel's direction on the long sixth when he made a 25 footer for birdie and Clarke missed from six feet.
Chasing his second successive win, Schwartzel stood 18 under par par, Clarke was 15 and two more South Africans, James Kamte and Keith Horne, were one further back.
Clarke's hopes nosedived further when he three-putted the seventh and Schwartzel saved par from the green. Both birdied the par five eighth, but at the turn Schwartzel was 19 under and Clarke shared second spot with Kamte on 15 under.