The 29-year-old Schwartzel went the last 62 holes of the Alfred Dunhill without dropping a shot after a double bogey on No. 10 in his first round his last slip. He birdied No. 5, No. 6, No. 8 and No. 13 in his final round for a comfortable win from England's Finch, who finished on 13 under.
Finch opened with four birdies in his first nine playing alongside Schwartzel to challenge for the lead, but paid for a wayward tee shot with a bogey on No. 11 and then made a double-bogey six on No. 14 to effectively end his challenge after Schwartzel had birdied No. 13.
English pair Dyson and Fisher were tied alongside France's Wattel seven shots behind Schwartzel, with Dyson finishing with a 67 to push up into a share of third.
Denmark's Soren Hansen (71) was in sixth on 9 under while Zimbabwe's PGA Tour player Brendon de Jonge finished with a two-over 74 to slip to a tie for 16th on 4 under, 13 strokes behind Schwartzel. Two-time major winner John Daly of the United States missed the cut at Leopard Creek in his second tournament back following right elbow surgery in July.