After an early scare when Hayley Raso struck the bar, the Ferns settled well, adopting a tweaked formation from previous outings.
Mayne set the side up in a 4-1-4-1 shape to provide more defensive solidity while still allowing runners from midfield to break forward when possible.
The adjustment paid off as the Ferns looked far more controlled than four days earlier and nearly took the lead in the 15th minute.
A well-worked corner routine saw the Ferns move the ball around the Matildas’ defence to find Grace Wisnewski in space, but her effort was blocked.
In the 18th minute, Australia opened the scoring. Alanna Kennedy reacted quickest to a rebounded shot after a Meikayla Moore block, firing a powerful effort into the net that Santos could do little about.
Despite the setback, the Ferns’ approach held firm, restricting Australia to few clear-cut chances.
Wisnewski had another opportunity around the 40-minute mark after Taylor won the ball back and threaded a superb pass to the attacker as she drifted into the box.
Her effort required a strong save from Teagan Micah to keep the score 1- 0 at the break.
As in Friday’s match, New Zealand had a good shout for a penalty early in the second half when Gabi Rennie was pulled back in the box while attacking a cross, but the referee waved away the appeals.
While the Matildas enjoyed the majority of possession, the Ferns did well to limit their threat for much of the second half.
The 66th minute saw Longo enter the field for her 144th and final Football Ferns cap, a special moment for her and the team.
With 20 minutes remaining, Australia doubled their lead in extremely unfortunate circumstances for the Ferns.
Katie Kitching was struck forcefully in the face by the ball, knocking her to the ground, and the rebound fell to Raso, who powered it home, a finish that would not have been possible had Kitching not been down in clear discomfort.
With moments remaining, Longo came close to pulling one back when she turned her marker superbly before whipping an effort towards goal, but fellow substitute Kelli Brown’s flicked header sent the ball just over, ending the game at 2-0.