(Reuters) - Thailand's Prom Meesawat topped the leaderboard after the final strokeplay round with a five-under-par 67 in the World Super 6 in Perth on Saturday, while overnight leaders Brett Rumford and Lee Westwood crashed out.
Play will switch to matchplay between the top 24 players on Sunday, with five rounds of six-hole knockout matches to determine the winner at Lake Karrinyup Country Club.
Meesawat will have a bye into the last 16 after finishing 12 under overall, two shots clear of clear of Dane Thorbjorn Olesen, American Sean Crocker and Australian Lucas Herbert.
Englishman Sam Horsfield, Japan's Yisaku Miyazato and Australians Brad Kennedy and Dimitrios Papadatos secured the other four first-round byes after finishing at eight under.
It was a day to forget for pre-tournament favourite Westwood and defending champion Rumford, who both carded six-over rounds of 78 to bow out of the event.
The 33-year-old Meesawat went on a blistering run from the tenth and scoring three consecutive birdies, including a monster putt on the 12th. He dropped a shot on the 13th but gains on the 15th and 17th took him clear of the field.
"I did well for the last two days, I only missed a couple of shots to put myself in the top position," Meesawat said.
"Very happy to finish first but still a lot of golf for tomorrow and I think it's going to be good fun.
"It (a win) means a lot. I'm going to earn my European Tour card and it's going to be the first win for me on the European Tour."
There was a nine-man playoff for the final eight spots with Italian Andrea Pavan, South Korean Yikeun Chang, Australian Callan O'Reilly and Thai Poom Saksansin all progressing with pars at the 18th.
South African Zander Lombard, Australian Stephen Leaney and Japanese Satoshi Kodaira also secured their spots with pars before Thai Kiradech Aphibarnrat edged out Anthony Quayle of Australia in a sudden-death battle.
(Reporting by Hardik Vyas in Bengaluru; Editing by Clare Fallon)