The Australians scored the first three tries of the game, and then put in a sterling defensive effort to claim victory.
The Ferns lost Lanulangi Veainu inside the first three minutes of the game, after she had to leave the field following a heavy tackle.
That seemed to upset the women in black, and they gifted Isabelle Kelly the first Jillaroos try when they failed to collect a bouncing kick.
Brittany Breayley crossed for the Australians again in the first half, before Chelsea Baker scored again in the second for the Jillaroos.
With four minutes remaining, Tanika-Jazz Noble bagged a consolation try for the Ferns.
Jillaroos 14 (Isabelle Kelly, Brittany Breayley, Chelsea Baker tries; 1 goal) def. Kiwi Ferns 4 (Tanika-Jazz Noble try). Half-time: 10-0.