Dragons RFC hooker Molly Reardon grabbed a brace on home soil as Wales scored at the death to edge Australia a thrilling encounter at a rocking Rodney Parade.
With the game tied at 24-24, Kate Williams crashed over from close range to give the hosts a first ever victory over Australia.
Walleroos wing Maya Stewart and Keira Bevan had exchanged tries in a closely fought first half.
Reardon then crossed either side of a Caitlyn Halse try, while Tabua Tuinakauvadra's late effort looked to have salvaged a draw for the Wallaroos.
But Wales had other ideas and their driving maul once again proved a deadly weapon.
It was a welcome win for Ioan Cunningham's side who meet Australia again in eight days in their WXV2 opener in Cape Town.
"I came on a lot earlier than I thought but Rosie (Carr) had set the platform and I just had to carry it on. It was really nice to get two in the bag," said Reardon after the game.
"We've worked really hard on our lineout, coming off the back of a couple of losses, and we stuck in there today.
"The girls put in a good shift and I was the one who got over the line with the glory in the end."
