Aaron Finch has urged his battered Australian team to be "ultra-positive, ultra-aggressive" when they face Sri Lanka on Tuesday after their Twenty20 World Cup title defence was dealt a major blow by New Zealand.

The hosts were hammered by 89 runs in Sydney on Saturday evening as they slumped to their second-biggest defeat (by runs) and worst ever at home after being skittled for 111 with 17 balls left chasing New Zealand's 200-3.

It was their first loss to New Zealand on home soil, in any format, since 2011.

"The fact that we've lost one game, yes, it's a heavy loss and it hurts our chances, no doubt. We can't dwell on that, we can't change it," said Finch.

"All we can do is concentrate on the next game and prepare really well for that against Sri Lanka (on Tuesday) and see how we go.

"We've taken the fate out of our own hands, I think to a point. We need to be ultra-positive, ultra-aggressive, and I'm sure that we'll all do that."

Australia never recovered from the sizzling start made by New Zealand openers Finn Allen (42 off 16 balls) and the brilliant Devon Conway (92 not out from 58).

They mercilessly took apart Australia's revered pace attack of Mitchell Starc, Josh Hazlewood and Pat Cummins in a way few have managed before, and there was no way back.

In reply, Australia never got a decent partnership going, with no player scoring more than 28 despite a good batting surface and familiar conditions.

But opener Finch, who flopped again as his poor run of form persisted, insisted there was no need to fiddle too much for Sri Lanka in Perth.

"We still feel as though we've got the right structure of team and we've got the right players to win the World Cup," he said.

"Obviously it's taken a big hit with the net run rate. When that happens, you need to play well. We need to get better quickly.

"Like I said, you need a bit of luck in T20 cricket as well as in such a brutal tournament. I think we've still got the right structure of the team, there's no doubt about that."

- Tremendous -

Conway was outstanding in carrying his bat, with his unbeaten 92 coming from just 58 balls, joining a select group to make 90 or more at a World Cup.

He was keen to share the spoils, insisting it was a team effort.

"I think for us it's close to a perfect game as a collective unit. We always say we want to start well, put teams under pressure," he said.

"I think the way Finn Allen batted in the front was tremendous and put them under pressure.

"We did well with the ball as well. We put it into good areas, put them under pressure. Yeah, it was a pretty good game for us to start the tournament."

They now shift to Melbourne for a clash on Wednesday with Afghanistan, whose biggest strength is their globe-trotting spin quartet of Mohammad Nabi, Rashid Khan, Mujeeb Ur Rahman and Qais Ahmad.

Conway said the Black Caps would not be changing their approach.

"We've got a process we try and stick to. Every game is another game," he said.

"We've got to focus on the things we can control and take each day as it comes."

No time to waste at T20 World Cup: South Africa skipper

South Africa captain Temba Bavuma vowed Sunday his team will come out with all guns blazing in their Twenty20 World Cup bow in Australia, with no time to ease themselves into the tournament.

The Proteas have a poor record in global events, never winning a World Cup or reaching a final in either short-ball format. They failed to make the T20 World Cup semi-finals a year ago on net run-rate.

Bavuma's side meet resurgent qualifier Zimbabwe in an all-African clash in Hobart on Monday to get their Ausralian campaign under way with the pressure on.

But he said they were up for the challenge.

"We have Zimbabwe as our opening game. There, everything that we've spoken about in our meetings and our preparation, we'll be looking to execute them as well as we can," he said.

"We obviously want to start on a positive note. We don't want to kind of ease ourselves into the tournament. There really is no time to do that.

"Tomorrow will really be an opportunity for us to execute our skills and our plans accordingly."

Bavuma himself is desperate for runs with his batting form so poor he was overlooked in the auction for South Africa's new T20 franchise competition.

He followed that by scoring only three runs in three innings in their recent T20 series in India.

Making matters worse, he recently fell ill to further hamper his preparations.

"I was out of action the last week or so in India with sickness. I came here to Australia still kind of recovering. But I've gotten over that," insisted Bavuma, who was appointed South Africa's white-ball captain in 2021.

Zimbabwe booked their berth in the Super 12 at the expense of Scotland in round one on Friday, to continue their good form under coach Dave Houghton, Zimbabwe's first Test captain back in 1992.

They have promised to cause "as much damage" as they can and Bavuma is wary, but confident.

"We know what we're going to do. We know how we're going to do it. And we're all quite comfortable around all of that," he said.