'Matured' McKenzie ready for All Blacks flyhalf chance as World Cup approaches

It will be McKenzie's third start at flyhalf in his 41st test, with the position switching between Richie Mo'unga (29) and Beauden Barrett (32) in recent seasons.

With electric pace and a raking boot, the 28-year-old has thrilled crowds with his attacking instincts for years but was sometimes marked down for being too flamboyant when sound game management was required.

That criticism has fallen away after steering the Chiefs with aplomb in their run to the Super Rugby Pacific final.

Often deployed at fullback to great effect in the past, McKenzie locked down the Chiefs' 10 shirt and never looked back.

In a sign of All Blacks coach Ian Foster's faith, he will take kicking duties off the tee from centre Jordie Barrett (26) against the Pumas in Mendoza as they launch their Rugby Championship defence in the lead-up to the World Cup.

"My game's probably matured a little bit more than what it has in the past," McKenzie told New Zealand media.

"I used to run myself into trouble a bit, and put the team under pressure.

"I've learnt that kicking is a big part of being a playmaker, and having that experience this year with the Chiefs has been great."

Mo'unga will run off the bench while Beauden Barrett will start at fullback against the Pumas, and the time-honoured tradition of debating which player should start where will rage on in New Zealand.

McKenzie is aware his promotion may be short-lived but is thrilled to get the chance to bring a point of difference.

"Obviously, Richie and Baz (Barrett) are playing great rugby, so I wouldn’t say the jersey’s mine whatsoever,” he said.

"But it is an opportunity. It's just about just playing my game.

"Obviously, we've got a game-plan but you just want to be yourself, be instinctive and play the rugby we have tried to play all year.

"That'll be what I'm trying to do on Saturday, just do my job."