'It means a great deal to win our national Open and again to win here at Durban Country Club,' said Clark, who also won this in 2002. 'Think my next goal must be to win it somewhere else! I think it is one of South Africa's great courses, it really does challenge the players and to win round here I know I have played good golf.'
Darren Clarke, who almost missed the cut at Durban Country Club, made up for his uneasy play on Thursday and Friday with rounds of 67-67 on the weekend to climb all the way into a tie for fourth. Clarke was joined by Nick Dougherty, James Kingston and Graeme Storm.
Clark forged a four-way tie for the lead with a 68 on Saturday and carried that momentum into the final round. He tallied his first birdie of the day at the par-5 third and began to break away from the pack with a birdie at the par-4 fifth.
The South African, who grew up near Durban and played this course several times in his youth, added another birdie at the par-5 10th to distance himself even further from his competitors.
While the battle for second place was underway, Clark picked up a birdie at the 14th and birdied each of the last two holes for a convincing win.
'I'm extremely pleased because I felt a lot of pressure to play well this week,' Clark said. 'I think a lot of people expected me to play well but I hadn't played much golf coming into the week. However my game just felt like it was getting better and better and today was the best I had played all week.'
Schwartzel, who won the dunhill championship in December, ran off a pair of birdies on the front side and a birdie at the par-4 10th lifted the 20-year-old to minus-8.
He found trouble with a bogey at the 12th but responded with back-to-back birdies starting at the 13th. Schwartzel stumbled again with a bogey at the 16th but closed his round with a birdie at the 18th for a share of second.
'I'd have liked to have been a couple of shots closer and I thought if I could get to 11 under par then I might have a big chance,' said Schwartzel, who shot a 68. 'I didn't quite get there but I was happy with my effort overall.'
Havret birdied the third and collected two straight birdies from the seventh to make the turn at 9 under. The Frenchman fell off the pace with back-to-back bogeys starting at the 10th, however, but birdied two of his last five holes to complete a round of 69.
Clarke needed an eagle at the short par-4 18th on Friday to make the cut and the Ulsterman made the most of the weekend. On Sunday, Clarke mixed six birdies and a bogey for a strong finish.
David Howell, a teammate of Clarke's at last year's Ryder Cup, carded a 71 to finish eight shots back at 7-under-par 281 along with Titch Moore, Tjaart van der Walt and Gregory Bourdy.