Four years ago, Munster head coach Johann van Graan was part of the South Africa set-up that suffered a shock result at the hands of Japan.
This year's Rugby World Cup hosts had announced themselves on the global scene, shocking the Springboks in the pool stages.
It's a sign of the Brave Blossoms' progress that their upcoming clash against South Africa is a World Cup quarter-final in which they are not rank outsiders.
Johann Van Graan may hope to see his own nation progress to the semis. But Japan have impressed him nonetheless.
He was speaking to ex-Ireland captain Keith Wood for Off The Ball in Dublin.
"The Japanese have been very, very good in this World Cup," he said.
"To top your pool in a World Cup is no mean feat. They've beaten Ireland, they've beaten Scotland so they are deserved winners of their pool.
"I guess if South Africa had to choose, they would have chosen the Japanese. It's the first time they've been to a quarter-final of the World Cup and it's stage where South Africa have been constantly at since '95."
The 2015 Shock
He spoke of the impact of losing to Japan four years previously in one of Rugby World Cup's all-time shocks. But he also touched on the fact the Springboks bounced back from that setback.
"It was a very big moment in rugby, a big moment in sport the fact that the Japanese won that game," he reflected.
"All credit to them. They went for the set-piece in the final play of the game and they kept the ball and scored then in the corner.
"From a South African point-of-view, we came back. We beat the Samoans 47-8 and then beat the Scots in Newcastle and the Americans in the Olympic Stadium.
"And then we met the Welsh in the quarter-final and managed to get past them. We probably played against the best team of all-time, the All Blacks, in a very tense and very close semi-final at Twickenham that day.
"They went on to become the first team to win the World Cup back-to-back."
In terms of Sunday's match-up, he believes Japan will be buoyed by the home support as well as their squad stability. But he sees small margins settling it.
"I'd like to think the Japanese might have the attacking game, but certainly the physicality and the pure grunt of the Springboks will be a massive factor," he said.
"Anything can happen in sport, but I think the Springboks will beat the Japanese."
You can watch Johann van Graan's preview of the World Cup quarter-finals above. He also spoke to Keith Wood about Munster's 2019-20 season which you can watch in full below:
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