Aaron Finch won the toss and sent the Black Caps in to bat, but was left to rue the decision after New Zealand put a mighty 3-200 on the board.
Australia came up desperately short, making 111 in a chase that never got going and lasted just 17.1 overs.
At the Sydney Cricket Ground: New Zealand 200-3 (Devon Conway 92 not out from 58, Finn Allen 42 from 16, Jimmy Neesham 26 not out from 13; Josh Hazlewood 2-41, Adam Zampa 1-39) beat Australia 111 from 17.1 overs (Glenn Maxwell 28 from 20; Tim Southee 3-6, Mitchell Santner 3-31, Trent Boult 2-24) by 89 runs.
