Henrik Stenson turned in 31 to take a one-shot lead midway through the first round of the Nedbank Golf Challenge in Sun City.
The Swede was a winner at Gary Player Country Club in 2008 and made five birdies in his opening nine holes to sit a shot clear of Branden Grace, Marc Leishman and Ross Fisher.
The 2013 Race to Dubai winner had been unwell in the build up to the event but showed no ill effects as he opened with two birdies and claimed two more on the sixth and the seventh.
He was to the left of the green with his second shot on the par five ninth but put his third close and a tap-in birdie moved him clear.
Leishman set the clubhouse target at four under after an unblemished 68.
The Australian had been in the first group out and had an early contender for shot of the day with just his second stroke as he played out of some nasty stuff on the right to about four feet. He missed the birdie putt but made gains on the fifth and ninth to turn in 34.
Further birdies followed on the 14th and the last to set the early target.
Fisher has an excellent record at this event, never finishing outside the top five in his three appearances so far, and last year's runner-up was four under through 13 holes.
The 35 year old parred the first but then made a hat-trick of birdies from the second as he put his second shot at the third to inside two feet and drained a 30-footer on the next.
Seven straight pars followed before he put his tee shot on the par three 12th to five feet and the Englishman was once again in contention in North West.
Home favourite Grace was also in a share of second with four birdies in his first 11 holes. The six-time European Tour winner finished in the top ten at the Alfred Dunhill Championship last week and birdies on the second, third, ninth and tenth continued his positive start to the season.
Defending champion Danny Willett was then at three under after birdies on the first, second and fifth while countryman Matthew Fitzpatrick had gains on the second, third and tenth.
American Robert Streb was also three under after four birdies and a bogey in his first 16 holes alongside Jaco Van Zyl who had three birdies through ten.
Tommy Fleetwood, Russell Knox, Louis Oosthuizen, Andy Sullivan and Bernd Wiesberger were then at two under, a shot clear of Keegan Bradley who was having a remarkable round.
He recovered from a triple-bogey on the first with five straight birdies but then dropped two shots in a row before a birdie at the 11th got him to one under.
