Green is outright leader at nine under after producing a stellar third round on Saturday at Adelaide's Kooyonga Golf Club.
The world No.9 fired a four-under 68 and holds a one-stroke buffer from Argentina's Magdalena Simmermacher (eight under).
The duo are set for a Sunday showdown - the next-best in the chasing pack are South African Casandra Alexander and Agathe Laisne from France at five under.
Australia's Karis Davidson and Kirsten Rudgeley are four under, but the hopes of the locals producing a first winner at the Open since Karrie Webb in 2014 rest squarely with Green.
The West Australian carded six birdies and two bogeys on Saturday and, while revelling in the home hype from large galleries, said keeping calm would be vital on Sunday.
"Just making sure that I'm not getting too ahead of myself," Green said.
"I'm probably going to put too much pressure on myself tomorrow and expect everything to go close and go in.
"And sometimes that's just not what the case is.
"I have just got to stay focused on what I can do - and I know there was a couple of good rounds from people playing a little bit earlier today.
"So (I'm) just focusing on what I'm doing and controlling what I can."
Should Green triumph, she will become the fourth local winner of the Open, joining five-time champ Webb, Jan Crafter and Jan Stephenson.
"Tomorrow morning, depending on tee times, I might have to distract myself a little bit - maybe go out for breakfast," Green said.
"But I'm super excited.
"I really hope more people come out and that the crowds will get bigger.
"It looks like it's going to be a little warmer, hopefully that means the course firms up because there was a couple of times where I thought it was going to bounce a bit bigger, but it didn't.
"Hopefully not too much wind (tomorrow) because it got pretty gusty those last few holes.
"I hit a lot of good wedge shots over the last two days and it's being able to capitalise on those shots, because there's a lot of times where you don't have easy shots in.
"And the putter has also been kind to me, so hopefully I can have all that tomorrow."
Steph Bunque (two under) and Kelsey Bennett (one under) are the only other Australians in red figures.
Australia's triple major winner and world No.4 Minjee Lee (four over) slipped from contention, shooting a troubled five-over 77 on Saturday.
Compatriot and fellow major winner Grace Kim is two over after signing for a one-under 71.
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