Coach Wayne Smith and his selection group were left with plenty to ponder as the Australians hit the ground running to rock the New Zealanders and silence their crowd.
Smith said their World Cup inexperience showed in how the New Zealanders started the game. It also hit home the need to complete individual preparation well. The Black Ferns were out-muscled early in the game.
"That's a concern in terms of the way we prepared.
"We seemed to be frenetic, and not at our best. But we had a good halftime, nice and calm and nice and specific. Credit to the girls, they came out and put their game on the park."
They had known what to expect, considering it was the fourth time they played them in 2022.
"They have given us more difficulty than any other team this year, so credit to them, I thought they played well," he said.
Captain, and first five-eighths, Ruahei Demant said that given their lack of exposure to World Cup rugby, she was pleased with how they closed off the first half and then with the way their second-half substitutes put their energy into the effort to lift the side.
It had been an occasion bordering on the surreal, she said.
"It was electric [at Eden Park]. To think that all these people have come here to support women, but, most importantly, to support the Black Ferns, is still quite unbelievable.
"I know that all of us tried to be present in the moment, and it was surreal singing the anthem and hearing the echo of the stadium – that's something we are not used to.
"But hearing their support, and being able to feed off that as the game went on, I would hate to be Australia at the end of the game."
Demant said Australia got out to their 17-0 lead in the first quarter because the Black Ferns couldn't get into the game.
"I think we were playing in to their hands, and not playing our game. Once we managed to flick that switch, and get into our groove, it was a lot of fun."
Part of their preparation for their next game, against --, will involve reviewing why they hadn't started as they wanted and why it took them so long to get into the game.
It also helped to have the speed and skills of wings Portia Woodman and Ruby Tui, who shared five tries in the win.
That was possible because of the way the Black Ferns' forward pack went to work with their power game.
"They [Woodman and Tui] still had a lot of work to do to cross the line, but it is a lot easier to attack when our pack is going forward, so, full credit to our forward pack because, when they rolled up their sleeves and got to work, it was a lot easier for us backs to attack off a good platform."
Tui said she knew what it was like to be down 0-17 to the Australians.
"I've been in that position way too many times. The Aussie-New Zealand rivalry is something you can't script. It is something special. I know it [rugby] is not the national sport there, so I always have respect for them growing the game over there, and bringing it to us, it was awesome."
Tui said the players knew they had to grow quickly because the strength in the side meant competition required players to bring out their best.
"If you don't someone else will step up. There is pretty hot competition in our team right now."
The Black Ferns take on Wales in their second Pool A clash at 3.15pm on Sunday 16 October at Waitakere Stadium.