Four years ago, the Brave Blossoms pulled off one of sport's greatest shocks with a breathless 34-32 upset of two-time world champions South Africa on England's south coast.
Eddie Jones, architect of the "Brighton Miracle" as it came to be known, had taken Japan from "joke team" - in the Australian's own words-- to giant-killers.
But Joseph's Japan could go a step further and reach the quarter-finals for the first time after an astonishing performance against Ireland, who came into the World Cup as the top-ranked team in the world.
"With 50,000 fans and 40,000 in red jerseys, it makes you really proud," said the former All Black, almost in a whisper, after the match.
"We obviously had a plan and we executed it."
It won't have made comfortable viewing for Scotland, who were battered 27-3 by Ireland in their opening game and face the Japanese in a potential winner-takes-all clash at Yokohama a little over two weeks from now.
"Ireland didn't frighten us at all," said winger Kotaro Matsushima, hat-trick hero of Japan's 30-10 win over Russia in last week's tournament curtain raiser.
"They were just kicking it. Every one of the players made our tackles, so we felt in control."
The way Japan hit back after tries from Garry Ringrose and Rob Kearney inside 20 minutes - from fly-half Yu Tamura's cool kicking to a dazzling try from Kenki Fukuoka that put the home side in front just before the hour mark - almost defied logic.
- Tenacious defence -
No longer able to rely on the element of surprise after humiliating the Springboks in 2015, Japan played with a real swagger in possession and displayed tenacious defence to see the game out.
"Finally we're free of all that South Africa talk," said scrum-half Fumiaki Tanaka.
"It's not just about South Africa -- we've shown that nothing is impossible."
Ireland prop Cian Healy admitted Japan's intensity had suffocated the pool favourites.
"Japan played an incredible brand of rugby," he said. "From the start there was wave after wave of constant pressure."
Japan will be expected to beat Samoa next weekend before the crunch game against Scotland.
But regular captain Michael Leitch, who came off the bench to ignite Japan on Saturday, insisted the Brave Blossoms still had a job to do, noting they won three games at the last World Cup and still failed to reach the last eight.
Telling in the build-up to a game Japan were given little chance of winning, however, was the relaxed demeanour of the players.
Assistant coach Tony Brown was also spotted on the eve of the game drinking a beer outside a pub in the city of Hamamatsu, posing for photos with Japan fans.
But the Japan players were all business after allowing themselves a cheeky beer in the locker room to toast their monumental victory.
"We believed we could beat Ireland and we put in a complete performance," said Leitch.
"But now we're focused on Samoa, who are a very physical team. Last night will mean nothing if we don't win our next two games - we have to keep our heads and go again."