Some of that belief would have been chipped away last night, with Australia clearly the slicker, more creative and, yes, more aggressive side.
Motivation also played a big role.
It is not often the world champion Diamonds side is upstaged, let alone in such a comprehensive fashion. The 10-goal margin was Australia's second biggest loss to their arch rivals in seven years.
The loss sparked an obsessive pursuit to right the wrongs in tonight's opener, particularly from their captain Caitlin Bassett. The Australian sharpshooter was benched in the third quarter of the Quad Series finale after being outplayed and outwitted by rookie defender Kelly Jury, who was playing in her maiden test against the Diamonds.
This time it was Jury who was dragged, with the 21-year-old replaced by livewire defender Temalisi Fakahokotau late in the second quarter having struggled to cut off the flow of ball into the Australian shooting circle.
The Diamonds attack end had a much better rhythm to it last night, with the addition of Susan Pettitt and, later, Steph Wood, at goal attack adding more speed and precision in the play-maker role. Both players sat out the Quad Series.
Bassett said after a disappointing effort in her last outing, she was pleased to be able to put some things right.
"I think our midcourt were fantastic tonight, they definitely make my job easier when they're getting the ball moving and they were getting the ball on circle edge and both Steph [Wood] and Susan [Pettitt] did an amazing job of feeding tonight as well, so it was good to see some changes," said Bassett, who produced a return of 39/43.
For the Ferns, the damage was effectively done in the first quarter.
Having absorbed the lessons from Invercargill, in which they were blown off the court in the first spell by a hungrier New Zealand side, Australia started with greater urgency, charging out to a 17-13 lead at the first break.
The deficit remained at four goals at each change of ends as the New Zealand side managed to claw it back every time Australia threatened to push the scoreline out further.
That fighting spirit helped paper over the cracks of what was at times a very ordinary performance from the Ferns.
"We were guilty of doing stuff that we shouldn't be doing at this level - soft passes, taking poor options, not chasing down loose ball," said Southby.
"It was just too many personal errors. We didn't do what we talked about in the game plan so that was really disappointing."
Southby has limited time to address these issues ahead of Sunday's second test in Christchurch. The series will then move to Australian for the final two tests.
