The former Masters champion made the ideal start with a birdie from 18 feet on the second, only to bogey the third after a wayward drive finished behind a tree and meant the South African could only find a greenside bunker with his approach.

However, the world number 43 responded with birdies on the sixth and seventh and then holed from 10 feet for an eagle on the par-five ninth for the second day in succession.

That took Schwartzel to 13 under par, four clear of playing partner Zander Lombard, who had covered the front nine in 34 with three birdies and two bogeys.

South Africa's Dean Burmester, who was third here last year, was a shot further back after five birdies in seven holes took him to the turn in 31.

Lombard's bogey on the 10th gave Schwartzel the luxury of a five-shot lead, but the 31-year-old promptly hit a wild tee shot on the 11th to drop his second shot of the day.

Another poor tee shot on the par-five 12th was fortunate to avoid serious trouble and Schwartzel took advantage with a superb chip from short of the green to set up a tap-in birdie, with Lombard doing likewise to remain four behind.