Steve Borthwick is unsurprised by Japan's stunning victory over Ireland after declaring the World Cup hosts now face tier-one opponents with the expectation of winning.
A 19-12 triumph over the Pool A heavyweights in Shizuoka has set the first Asian tournament ablaze, four years after the Brave Blossoms produced the greatest upset in rugby history by toppling South Africa.
Borthwick, England's forwards coach, helped mastermind the Springboks ambush as part of Eddie Jones' coaching team and the result was responsible for transforming the game in Japan.
And now the heroics against Ireland, who entered the World Cup at the summit of the global rankings, has offered sight of a first ever quarter-final.
"It wasn't surprising. It was a good game to watch. They played very well, they played smart," Borthwick said.
"The big thing was the tenacity with which they play. They were impressive in that regard. They've got speed, they've got talent and then that tenacity.
"What 2015 did undeniably was lift rugby within Japan and it's really important that they are effectively backing that up, building on what has been done before.
"Their coaching team of Jamie Joseph and Tony Brown has done a great job, building that team throughout the four years from 2015 to now.
"A big area of development prior to 2015 was making the team believe they could win and having the expectation of winning, so to see them play the way they did was great.
"There is an expectation now that Japan can win. If you look at their history in World Cups prior to 2015, it does not make pretty reading. Now Japan go into these games expecting to win.
"It was great to see and I think it is good for the competition to see the home team do so well. For the host nation to have a game and a result like that without question helps."
Japan will climb to eighth when the next set of global rankings are released - the highest position they have ever held - and Borthwick expects the bold decision to stage the World Cup on these shores will be rewarded.
"There's a lot of competition for sport over here. Baseball gets a lot of support and rugby had dropped down quite a bit before 2015," the former England captain said.
"The team in 2015 looked a lot at how they could grow the popularity of the sport and they felt a lot of responsibility for doing that.
"It's a big population here and rugby has a long history here. The success of the Japan side could be fantastic for the growth.
"Every time I've been back to Japan since the last World Cup, on recces looking at facilities, we have seen rugby's growth. You see the popularity of it.
"When you see the excitement in the stadiums with the supporters they have, the passion for the game is there.
"As more and more people are exposed to the sport during this tournament, it can grow even bigger."
England have swapped Kobe for Tokyo, where they will be located for the remainder of the group stage to play their pivotal matches against Argentina and France. Jones names his team to face the Pumas on Thursday.