The event consists of three strokeplay rounds and two cuts, before the top 24 play off in six-hole matchplay duels.
"It will be a mindset thing where you've got to realise that the strokeplay is just a qualifier to get into Sunday," said Oosthuizen.
"It's a bit like when I played the qualifying school."
Oosthuizen is effectively the defending champion having won the event's predecessor - the Perth International - at the same Lake Karrinyup Country Club venue last season.
The 34-year-old South African believes that the format will create a climatic final day's action as the final 24 take each other on in a knockout matchplay tournament.
"You'll see probably a few more riskier shots which you wouldn't see in stroke play. It should be a very exciting Sunday," added Oosthuizen.
The top eight go straight into the last 16, while the remaining 16 will be drawn together in head-to-head matches to decide the other eight spots. From there it is straight knockout until there is a winner.
"You'll see probably a few more riskier shots which you wouldn't see in stroke play. It should be a very exciting Sunday," added Oosthuizen.
The top eight go straight into the last 16, while the remaining 16 will be drawn together in head-to-head matches to decide the other eight spots. From there it is straight knockout until there is a winner.
