Finn Allen said the Black Caps wanted to throw the first punch in their T20 World Cup opener against Australia. The young slugger and his teammates did not miss.

Allen staggered the defending champions, Devon Conway put them on the canvas and the bowlers never let them up as New Zealand earned an 89-run victory at the SCG tonight.

That marked Australia’s biggest defeat in a T20 World Cup match, never able to recover from the opening batsmen’s blitz.

After being sent in, Allen (42 off 16) showed why he had usurped Martin Guptill and Conway (92no from 58) continued his outstanding form, seeing the Black Caps post a formidable total of 200-3.

Tim Southee then took 3-6 as all five bowlers contributed - aided by a stunning, running, full-stretch catch from Glenn Phillips - and New Zealand ended a long drought across the Tasman.

The Black Caps had been bullied by Australia on their home turf since the famous 2011 test triumph in Hobart. Tonight’s victory in Sydney won’t quite be held in similar esteem but taking down the heavyweights does position them nicely in this tournament.

It also extracted a measure of revenge after Australia left the Black Caps dazed in last year’s T20 World Cup final, a match Conway missed after breaking his hand while punching his bat in frustration during the semifinal.

Tonight, after 11 months of licking their wounds, he and Allen came out swinging.

“We talked about it wanting to throw the first punch against them and not let them settle,” Allen said. “So it was just about committing to that and being fearless.”

Having only recently deposed Guptill as the Black Caps’ chief aggressor atop the order, some fear would for Allen have been understandable. This was by far the biggest moment of his career.

But the 23-year-old was unbowed as he took strike against Mitchell Starc, freeing his arms on ball one, hitting ball two to the fence and smashing ball three over it. Allen would plunder 14 runs down the ground from the veteran paceman’s first over, flourishing on the front foot to immediately extinguish Starc’s fire.

Conway soon followed his partner’s lead, collecting a couple of boundaries as the openers took 15 off the next over from Josh Hazlewood, the world’s top-ranked bowler.

Allen was then fortunate to survive when Adam Zampa dropped a tough chance from Pat Cummins. But he cherished that life by making Marcus Stoinis the third Australian he hit out of the ground, bringing up his side’s 50 with a towering blow over the bowler’s head.

The Wellington batsman was yorked by Hazlewood to begin the fifth over but by then his job was done, with New Zealand reaching 60-1 at the quarter mark.

Kane Williamson’s introduction saw the scoring rate fall as 16 balls passed without a boundary, a slump ended when Conway cracked Zampa over long on. And another middling innings from the skipper ended when he was trapped trying to reverse-sweep Zampa, falling for a run-a-ball 23 and squandering a review in the process.

That wicket was likely a blessing as it allowed Phillips and Jimmy Neesham more time in the middle, the latter bringing up 200 with a final-ball six as Conway ended unbeaten in the 90s for the third time in T20Is.

Australia’s innings, like their opponents’, began in ominous fashion as David Warner saw his stumps displaced when Southee’s first delivery took a couple of deflections off both player and bat. But if that dismissal was fortunate, there was little luck involved in what was to follow.

Mitchell Santner’s early introduction paid off with the wicket of Aaron Finch, and once Southee removed danger man Mitchell Marsh, New Zealand would have been experiencing emotions not felt in a decade: dominance over Australia at home.

Their supremacy never threatened to slip as recent fielding struggles were banished and Southee, appropriately, applied the finishing touch, leaving the Black Caps riding high ahead of Wednesday’s game against Afghanistan.

“It was an outstanding day,” said Williamson. “Finn Allen at the top set the tone and it was another class innings from Devon.

“I thought the fielding and the bowling was outstanding - we know how good this Aussie side is and they’ll keep coming hard. But the boys showed a lot of ticker and took their catches.

“It’s a funny old game.”