The world No.6 showed her class at Kingston Heath to post an opening score of six under, one stroke behind leading duo Hyojin Yang and Green's best friend Su Oh.
Even par through eight holes, Green birdied six of the last 10 on Thursday to underline her favouritism to win her first national crown.
The fact that she did it barely 24 hours after arriving in Melbourne from the US, where she played in the LPGA Tour's season-ending tournament, and without a practice round due to wild weather, made it even more remarkable.
"It was not my best start, but obviously it was nice through the back nine to make some good birdies on some tough holes," the 27-year-old said.
"The last couple of hours, I felt like I didn't really know where I was and it was kind of hard to remember what the course was like because obviously, I didn't get to see it.
"It was obviously a really good round, I think probably because I had no real expectation."
Anything you can do, I can do better… — Golf Australia ⛳ï¸� (@GolfAust) … @hannahgreengolf, probably! ğŸ¤#AusOpenGolf pic.twitter.com/vV05KWB9xtNovember 28, 2024
Green said she enjoyed the dual-gender format, now in its third year, which came with the added bonus of playing alongside her male golfing husband Jarryd Felton.
But she feels the timing of the tournament doesn't work for the women, which was backed by compatriot Minjee Lee, who also had to make a dash from the US to play.
Initially voicing her concerns at the pre-tournament press conference, Green again said Australia was missing on seeing the world's best women in action such as Korda, who won the Open in 2019 at The Grange in South Australia.
"I do like playing the men and women together, but it doesn't work for the best female players to come down," the Paris Olympian said.
"Obviously with me arriving on Wednesday, it doesn't work with the LPGA schedule and I think it even collides with some of the LET (Ladies European Tour).
"So if you want the best of the best to come and play for the trophy, unfortunately, this isn't the time of year.
"I do wish it would go back to February just so we can have Nelly Korda, Brooke Henderson, all the girls that did come down to Australia (again) to compete for the trophy."
Hannah Green watches an approach during her opening round at Kingston Heath. (Con Chronis/AAP PHOTOS)
Despite storming to the men's lead at eight under, Lucas Herbert lamented the pin placement at Victoria, with the courses set up to cater for both sexes and all-abilities players.
"It's a little frustrating seeing where some of the pins are," Herbert said.
"I think we could go harder, and for a national open ... testing us with some harder pins."
Green also described the pins as "pretty generous".
"They obviously did try and tuck some pins on perhaps the shorter holes and holes that are easier, but I do think that if the men played at this course, the pins would be much more tucked," she said.
"They obviously want to make sure everyone gets to play in and they don't want the score to be too high.
"I do like playing championships where if you shoot one or two under, that's a really good score out there."
