TOKYO - Coming off a heavy defeat to South Africa, the task for Namibia gets even tougher on Sunday in Tokyo when they line up against a two-time reigning Rugby World Cup champion All Blacks team aiming to retake top place in Pool B.

New Zealand have won 16 consecutive matches at the tournament and all 30 pool stage games they have ever played, while Namibia is still searching for their first victory in 21 attempts.

"It's a massive opportunity and a challenge for our boys to pit their rugby thinking and physical prowess against the best team in the world," said Namibia's Welsh head coach Phil Davies.

"That's what we learned from playing them four years ago and nothing's changed."

One significant thing that has changed for the first time at this tournament is the player who will be pulling on the famous All Blacks No. 10 jersey at Tokyo Stadium (Ajinomoto Stadium).

New Zealand coach Steve Hansen has opted to tap Jordie Barrett for his first start at the position in international rugby, replacing incumbent flyhalf Richie Mo'unga to give the first-choice man some rest.

Barrett played on the wing in New Zealand's 63-0 dissection of Canada on Wednesday, scoring the opening try, but he did not feature in the match-day squad in the team's opening win over South Africa.

"It's a pretty special jersey -- a lot of great players have gone before me and the current players here. It's one I'm very grateful for and I'll treasure it," said the 22-year-old Barrett.

(Jordie Barret (L) storms past Canada winger Taylor Paris)

Such is the depth of talent in New Zealand that it is unlikely Barrett will even miss a beat against Namibia, despite his relative inexperience at the position.

"I've got bounced in and out of positions at training a little, not knowing I was going to play 10. But I do feel well prepared," he said.

Hansen is certainly not concerned that the selection may prove problematic.

"He has plenty of swagger. He's not short of it," he said.

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"He's not an arrogant boy. He's a humble kid. He will be looking forward to it. He will get out there and boss the team."

Adding to the mountain Namibia have to climb is the fact that a hungry Brodie Retallick returns from injury, his dislocated shoulder healed and ready to be put to use against the squad from southern Africa.

Hansen was full of praise for how the big lock got himself back to fitness ahead of schedule.

"He loves playing and to have something you love taken away from you, it's pretty easy to work hard to get back out there," the coach said.

Like their opponents, Namibia will also field a new face at the pivot position, bringing in Helarius Kisting in place of Cliven Loubser, who took a knock to his ankle in the team's heavy loss to their African cousins in Toyota.

Davies said the injury is not serious, but that he is happy to give Kisting, a player he said was something of a self-made man, a shot at marshaling from midfield.

"I have nothing to lose. I'm just going to leave everything on the field, knowing I've done my part," said Kisting. "Even if you don't have a good time, even if you screw up everything, just do something for them to remember you."