Darren Clarke fired a final round of three-over-par 76 to end in a tie for 20th place at the Volvo Champions event at the Fancourt Links in South Africa.
Clarke posted five bogeys and two birdies in his final round.
Michael Hoey finished back in 33rd on 16 over after a closing 82 which included three double bogeys.
Branden Grace won at the first play-off hole after Ernie Els and Retief Goosen had also finished 12 under and Padraig Harrington tied for 10th on four under.
Grace birdied the the first play-off hole, the 18th, while Els and Goosen both shot pars.
For Grace, it was his second tournament win in two weeks and he now enjoys a healthy lead at the top of the Race to Dubai.
Clarke had recorded scores of 74, 68 and 73 on the first three days of the reduced field event.
The Open champion carded three bogeys and a birdie on the outward nine of his final round on Sunday, and two bogeys and one birdie on the inward nine.
Hoey's disappointing last round included bogeys at the ninth, 15th and 17th holes.
The Belfast player also registered four bogeys, before finishing with a birdie at the par-five 18th.
Harrington fell down the field on Sunday after a 76 which included three birdies, four bogeys and a double bogey.