After being pushed surprisingly hard by Namibia in Tokyo on Sunday, All Blacks coaches and players were bombarded with questions from local media about the prospect of a marquee quarterfinal matchup with Japan.

As undisputed rugby royalty, the All Blacks have captured the hearts of the Japanese public almost as much as the home team, meaning a meeting between the two would be a national showstopper.

New Zealand coach Steve Hansen said the prospect of a knockout game against Japan would very likely test the allegiances of the hoards of Japanese All Blacks supporters.

"It will be a heck of a game from a crowd point of view because all of those great Japanese supporters that seem to get behind us probably might flip over and put on a red and white jersey," he said

"So it would be good if they are on the other side of the draw."

The All Blacks are near certainties to win their pool, which would put them on a collision course with Japan if the hosts finish second behind Ireland in theirs, which is possible but not a sure thing by any means.

It is just as likely Japan beat Scotland next Sunday to win Pool A and set up an almost as daunting game against South Africa.

Either way, Hansen said Japan's incredibly strong play so far, and the way the public has embraced the Brave Blossoms and the tournament, generally, has been wonderful to see.

"I am really enjoying that Japan is having a great tournament because it is great for rugby in this country, and one of the side products of this tournament outside of finding a world champion is to promote the game," the coach who piloted the Kiwis to the title in 2015 said.

The Brave Blossoms' Kiwi coaching connection is one reason the All Blacks have a healthy respect for them.

"I am not surprised with the likes of Jamie (Joseph) and Tony (Brown) and how they are tracking that Japanese team, they are well coached and they are getting them out there to play some good rugby," said New Zealand fullback Ben Smith of the Japan head and assistant coaches, respectively.

After their game on Saturday, Japan was among the statistical leaders in a number of metrics, according to the Rugby News Service.

The Brave Blossoms had conceded the joint second-fewest penalties, had not seen a card of any color and were in the top-three in tackles per match. On attack, they were in the top-three in passes per match, behind only New Zealand and England.

New Zealand's Jack Goodhue singled out Japan's robust defense as a point he has been very impressed with.

"Japan is really going out there and their defense is dominating teams," the resplendently mullet-hairstyled outside center said. "Their technique is awesome and they are putting a lot of pressure on other teams. They are real threats for this World Cup."

Kiwi prop Angus Ta'avao put the home team's rise plainly.

"They have really set a standard for Japanese rugby, they have been building for a few years and with their inclusion in Super Rugby they have been able to put themselves to the test against high-quality rugby for a long time," he said.

"If we come against them, we know it will be a tough challenge."