Clark shot a 5-under 67 to match Goggin (69) at 9-under 270. New Zealands David Smail, the leader at 12 under with four holes to play, finished with a 75 to tie for third with Australians Robert Allenby (71) and Stephen Dartnall (72) at 8 under.
Smail double-bogeyed the par-4 15th and par-5 16th.
Im just gutted, Smail said.
Clark had given up hope of winning before Smail collapsed.
I didnt even consider there would be a playoff until about 30 minutes after I finished, Clark said. I was watching the TV, having a pie and chips, believe it or not, and thought I better get down there and warmup.
I feel bad for David the way he finished.
Goggin also finished second last week in the Australian PGA, two strokes behind Australian star Geoff Ogilvy.
I feel for David, really, Goggin said. He had the tournament. He was playing well. To have such a horror finish was brutal for him.