Australia's T20 leaders are revelling in death-hitting sensation Tim David, who showed his ice-cool closing abilities against the Black Caps.

David hit a clutch last-ball boundary as Australia reeled in New Zealand in Wellington on Wednesday night for a six-wicket win.

The 27-year-old came to the crease with four overs left in the trans-Tasman clash in Wellington, with Australia needing 44 runs from 19 balls after New Zealand posted an imposing 3-215.

That worsened to 32 off nine before David set sail, clubbing Adam Milne and Tim Southee for consecutive boundaries to steal an improbable win.

The Singaporean-born allrounder looms as Australia's X-factor at June's T20 World Cup.

"It's an exciting prospect to have Tim David finishing games like that for Australia," coach Andrew McDonald said.

"There's a lot of mental strength to it, but there's also just a lot of skill, high-level skill.

"We've seen some great death-hitters over time ... but it's a scary proposition when he walks to the crease for any opposition bowlers."

David's path to stardom has been littered with knockbacks and missed opportunities, most notably from Western Australia, where he grew up.

However, he has flourished after a move to Big Bash rivals Hobart Hurricanes, winning several T20 contracts around the world, including The Hundred in England and the Indian Premier League.

"It takes a long journey," McDonald said.

"The finishing skills of Tim David, we've seen it all around the world and now we're sort of starting to see that really connect in Australian colours as well, so that's really pleasing."

Captain Mitch Marsh was at the non-striker's end for David's extraordinary dig at Sky Stadium, saying he was happy to stay there to watch David guide Australia home.

"From the moment he came out, he was really calm and knew exactly he wanted to do," Marsh said.

"He's just learning and learning.

"Over the last two years I've seen (David) dominate T20 comps around the world, and then coming on to the international stage and feel at home playing for Australia.

"What did we need, 16 off the last over? We thought two sixes early on in the piece would get it down to pretty much done, but Tim Southee bowled a couple of great balls.

"It was special watching, very proud of him."

While David had a lean Big Bash League with Hobart, averaging just 16 from nine innings, he has now produced in his past four national team knocks.

He was there at the death in all three matches against West Indies and again against the Black Caps, scoring unbeaten totals of 37, 31, 41 and 31, in all four scoring at more than two runs a ball.

With a 1-0 lead in the series, the Australians on Thursday travel to Auckland, where they will finish the series with two matches at Eden Park.

The fabled rugby union ground is New Zealand's biggest stadium, and promises two more high-scoring encounters given the short boundaries.

Waiting in Auckland is Aussie Matthew Wade, who missed game one to be with his partner as she gave birth.

"Congratulations to the Wade family," McDonald said.