Tokyo (AFP) - Eddie Jones once described Japan as a "joke team" - before the Australian lit the fuse that sparked an outrageous victory over the mighty Springboks at the 2015 World Cup.

Well, no one's laughing now after his successor, former All Black Jamie Joseph, steered this year's tournament hosts to the quarter-finals for the first time, creating history by beating Scotland 28-21 last weekend.

"Over these four weeks, make no mistake, Jamie Joseph's impact has been huge," said Japan's totemic captain Michael Leitch.

"He has sent all the right messages and pushed all the right buttons - he's been massive." One of sport's greatest upsets, on England's south coast in 2015, was turned into a movie in the run-up to this year's World Cup.

However, Japan's Brave Blossoms have topped the "Brighton Miracle" and are busy working on a sequel after finishing first in Pool A with four straight wins.

The title has been used already, but after beating Russia (30-10), Ireland (19-12), Samoa (38-19) and now Scotland - everybody's talking about Jamie.

Victory over Scotland in Yokohama on Sunday in the biggest game in Japan's history saw Joseph emerge from the shadow of Jones, the man who put Japanese rugby on the map.

"With Jamie's style the players have a lot more responsibility and accountability for their actions," Leitch told AFP in an interview before the World Cup.

"Because we did well at the last World Cup there's a lot of expectation," added Leitch, who will lead Japan out against South Africa in Tokyo for next week's quarter-final.

"But we've got a job to do and losing is not one of them." - Breaking point - If that 34-32 shock over South Africa four years ago was a textbook example of giant-killing, victories over Ireland in Shizuoka and Scotland in Yokohama were even more ruthless in the Japanese team's snarling tenacity and cold-blooded efficiency.

Japan's history-makers have played with a swagger in possession, while their suffocating defence can drive opponents to despair.

"We're probably on defence the most aggressive Japan team ever," said lock James Moore.

"Jamie's a great coach and he's brought this team so far already - both physically and mentally." Centre Ryoto Nakamura added: "Our rugby is built on the foundation Eddie gave us, but this team's taken it another step. The standards are higher now." Jones subjected the Japan players to punishing boot camps, pushing them to breaking point in preparation for the last World Cup.

Joseph reprised that tactic in the run-up to the 2019 tournament as the Japan side spent 240 days in camp this year honing their free-flowing rugby.

Joseph, who also carefully managed the Super Rugby schedules of his players to avoid burnout before the World Cup, believes he has the tournament's fittest side.

The killer combo of lightning-quick passing and a ferocious appetite for tackling Joseph has drummed into his players has made Japan an intoxicating watch.

- 'Never stop running' - "We never stop running in training," said full-back Ryohei Yamanaka of Joseph's lung-bursting workouts.

"The skill levels are higher than ever before but we've also got those miles in the bank." Fly-half Yu Tamura leads the World Cup with 48 points through four games, while winger Kotaro Matsushima is one of two players to have scored five tries.

However, Japan's pugnacious defence has underpinned their fairytale run, notably in repelling Scotland's second-half charge and frustrating an Ireland team who entered the tournament as the world's top-ranked side.

Once pulverised 145-17 by New Zealand at the World Cup, Japan have defied logic to reach the quarter-finals, with bookmakers offering odds of 50-1 against them winning their pool. Their heroics have seen them climb to seventh in the world.

But Joseph's technicolour side - 16 of Japan's 31-man squad were born overseas - are refusing to settle for the last eight.

Based in a hotel used in the Bond movie "You Only Live Twice", Japan's players are already plotting South Africa's downfall.

"We're not coming out next week to have a good time and lose," warned Leitch.

"We're coming to win."