Desvonde Botes matched McLardy's 67 to finish in second place at 13-under-par 267. Titch Moore fired a 4-under 66 to move into a tie for third place at 12-under-par 268. He was joined there by South African Keith Horne, who closed with a 2-under 68.
McLardy had his problems on the front nine, but rallied to birdie five of the final 13 holes for the win. He opened with a birdie at the par-5 third.
The South African faltered to a bogey at the following hole, but that wasn't the worst of it. He stumbled to a double-bogey at the par-4 fifth that dropped him back to the minus-11.
'On the fifth, I hit a 5-iron approach straight at the pin but it flew into the bush behind the green,' said McLardy. 'I tried to play it out of the bush but only moved it two yards and then thinned my fourth over the green, I two-putted for a six.'
He quickly rallied to regain his form. McLardy rolled home a birdie at the par-3 sixth and came back to birdie the eighth, another par-3, to get back to even par for his round.
Around the turn, he birdied the 11th at Wild Coast Sun Country Club to get to minus-14. He coasted in with birdies at Nos. 15 and 17 for the easy win.
'After the 17th, stupid stuff started going through my head again and I was thinking about speeches and all that crap, but I still had to get over the water on 18,' said McLardy.
Moore collected back-to-back birdies from the second, but dropped a shot at the sixth. He again made two straight birdies from the eighth and closed out his round with a birdie on No. 12.
Horne opened with a birdie at the fifth and closed out his front side with a birdie on the ninth. He birdied Nos. 13 and 15 to grab a share of second.
Michael Archer fired a 6-under 64 in the closing round to climb into a share of fifth place. He was joined at 11-under-par 269 by Andre Cruse (66), Scott Dunlap (67) and Marc Cayeux (67).
Michael Bothma posted a 65 to come in ninth at minus-10, with Nic Henning one stroke further back at 9-under-par 271 after a closing 67.