The Australians were ruthless from the first whistle, sinking a run of nine unanswered goals to lead 17-9 heading into the second quarter.
New Zealand made seven substitutions across the match to little avail while the Diamonds stuck with their starting lineup throughout.
"We were ready for a fired-up Kiwi team," Alexander said.
"They played very well against South Africa, better than they did against England, and we expected them to improve again.
"We knew we had to do the things that were important for us to shut them down, and what you saw today was the execution of that, paired with some very smart play."
It was a horror five minutes, and a mediocre other 55, for the Silver Ferns that cost them dearly.
A 9-0 Australian run midway through the first quarter dug New Zealand a hole they wwere not able to extract themselves from, and buried any hope that they could defend their Quad Series title.
After some tight tussles early in coach Janine Southby's tenure, yesterday's result signified the growing gulf between the two nations. This was the worst of the five straight losses.
It followed on the heels of 12 and 16-goal defeats in New Zealand's last two outings against the Diamonds - creating an unwanted candidate for the title of the worst three-game stretch in Ferns history.
Their 57-47 victory over Australia to steal Quad Series victory last year now seems like a massive outlier, with the Ferns now holding a 2-10 record under Southby against their fierce transtasman rivals.
The Ferns never recovered from their early struggles, in which saw a 6-6 battle rapidly evolved into a one-sided 15-6 scoreline.
Nine straight goals was the biggest run the Ferns had conceded since 2016 - also during a loss to Australia - and given their shaky earlier form - having lost to England and just edged past South Africa, a comeback was never likely to be on the cards.
So it proved as the Australians held their advantage and extended it.
Defensively, the Ferns were a mess early on, with Temalisi Fakahokotau often found out of position, or unfairly left alone with two attackers bearing down on her.
At the other end, the Ferns were coughing up possession, with 13 first-quarter turnovers. Bailey Mes accounted for six of them, in exchange for just four goals, and the problems led to mass changes.
Southby made 14 changes throughout the game as every player spent time on the bench.
It was perhaps the sign of coaching desperation, and all the musical chairs only created marginal improvements, at best.
Te Paea Selby-Rickit was the most effective of the substitutions, producing a far higher volume than Mes. Safer in possession and benefiting from more direct play, Selby-Rickit nailed 28 of her 30 shots, and must be pushing for a starting spot following her similarly solid showing against the South Africans.
When in shooting position, the Ferns were capable, hitting at a 48/58 rate, but they were rarely in that situation, with 34 turnovers seeing Australia hoist a remarkable 25 more shots than the Ferns.
Captain Katrina Grant said that their experimentation did not work.
"We've been working on a lot of things but we've been inconsistent with that," she said.
"The combinations that we've got on court today are ones that we've never tried - and this is time for us to try new things.
"We just need to go home and work on a few things."
With just two months until the Commonwealth Games, it will need to be a quick fix.
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- additional reporting: AAP
