Damian McKenzie tore apart the French defence when he came into the game at Eden Park on Saturday night.

As Damian McKenzie ran amok over the last quarter of an hour or so on Eden Park on Saturday night, one important box was ticked in the World Cup planning document.

This was the finisher the All Blacks want for the global event; the difference-maker they can bring off their bench late in a contest, and turn it on its head. This was their Beauden Barrett from the 2015 cycle.

And though the fleet-footed, diminutive Chiefs playmaker is a designated backup to Barrett at first five-eighths in this All Blacks squad, coach Steve Hansen confirmed on Sunday before decamping to Wellington that it's at fullback where he can expect to spend most of his time off the pine.

McKenzie came on in the 64th minute to replace Jordie Barrett at the back in the opening test against France, eventually won 52-11, after the All Blacks had trailed 8-11 at halftime.

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His impact was immediate, and vivid. He scored one spectacular try, just missed a second with a foot in touch, set another up with a slashing run, and seemed to find holes everywhere as the French defensive wall, so strong in the first half, came tumbling down.

Hansen was asked on Sunday if he felt vindicated, after some veiled criticism that the in-form Richie Mo'unga might have been a better option on his bench.

This, of course, failed to recognise that the princely Barrett will only be replaced in the event of injury. And that if the change is tactical, it takes place at fullback.

"I never get too worried about what other people think," he replied. "The only people's opinions that get tested are mine, Fozzie's (Ian Foster) and Foxy's (Grant Fox) when it comes to selection. One of the reasons we picked Damian was because we see him as an international fullback after last season, and it's more likely he goes on at fullback because we want to keep Beaudy on for 80 minutes.

"He (McKenzie) showed us again he's a pretty talented young man."

McKenzie was just rapt to come on at such a fortuitous time in the match.

"When I came on the boys started to get on a wee roll and I managed to get on the end of some good play. It was awesome, and it was pretty quick out there," he said afterwards.

In terms of position, there is no preference.

"I'm happy wherever I'm needed, wherever I'm called on. Tonight it was 15, and it was good to get back there with a bit more time. I really enjoyed it.

"I'm trying to bring energy and spark off the bench, and play my game. A few things fell my way at times, but I have a licence to play within the structures but have a go as well."

Ngani Laumape also enjoyed his new role as part of the bench mob, steamrolling the unfortunate Maxime Medard to score a spectacular try down the right touchline.

"I've never been the biggest person, and my parents always told me to run hard and tackle hard. When I'm in those moments I will back myself," he said.

"I saw TJ [Perenara] and he always tells me to back myself and pull the trigger. In that moment it was time for me to do what I do best."