“If I had a spare $10, I probably wouldn’t have put it on Japan to win that game myself.”

Those are the words of first five-eighth Kosei Ono on the 10-year anniversary of one of the greatest upsets in sporting history – when Japan stunned the Springboks with a last-gasp try at the 2015 Rugby World Cup in England.

The Brave Blossoms were 66/1 outsiders with some bookmakers ahead of their September 20 clash against South Africa in Brighton – but, down by only three points with time up on the clock, they rolled the dice and shocked the world to win 34-32.

It was no second-string Springboks side either, with the likes of Bismarck du Plessis, Victor Matfield, Schalk Burger, Pieter-Steph du Toit and Bryan Habana all named in the starting line-up.

Christchurch-raised Ono started in the No 10 jersey for Japan that day. He watched the final seven minutes on the sideline after he was substituted in the 73rd minute.

“We were just spectators by then. We were just riding the emotions with the crowd,” the now 38-year-old told Newstalk ZB’s Weekend Sport with Jason Pine.

Japan celebrate scoring their second try through Ayumu Goromaru in the 2015 Rugby World Cup match against South Africa. Photo / Photosport

“I just remember the crowd being really green [wearing Springboks jerseys] at the start of the game, in the warm-up and things, but as the game wore on, I don’t know, it just started to turn red [wearing Brave Blossoms jerseys]. It was almost like the Springbok[s] fans were cheering a good game.

“The seven minutes was a bit of a rollercoaster as such ... it was a pretty crazy finish to the game.”

Awarded a scrum penalty 5m out from the Springboks line as the fulltime hooter sounded, Christchurch-born Japan captain Michael Leitch was faced with the biggest decision of his rugby career.

They were trailing 32-29. A successful penalty kick from near the left-hand sideline would result in a draw with the then No 3-ranked rugby nation in the world.

But with a Springboks player in the sin bin, Leitch opted for another scrum in a bid to complete possibly the biggest upset rugby has ever seen.

The next four minutes were history in the making as Japan spread the ball to the right-hand touchline through multiple phases. They snapped it back left into the hands of reserve loose forward Amanaki Mafi, who fended off one defender and shovelled it off to Napier-born replacement wing Karne Hesketh.

Karne Hesketh scores the game-winning try for Japan against South Africa at the 2015 Rugby World Cup. Photo / Photosport

Hesketh, who left Hawke’s Bay to play in Japan six years earlier, sprinted for the left-hand corner and dove over in the 84th minute as the stadium erupted.

“[It was] like a miracle happened,” Ono said. “I’ve had a lot of people come up to me [saying] they knew where they were, who they were with and what they were doing at the time that it happened – because they were so shocked.”

Ono said he and Hesketh were in Dunedin years after the historic win when a university student grabbed Hesketh in a bar and said, “you put me through university because I had money on you to score a try”.

“It’s just little stories like that sort of pop up every now and then, which is pretty cool,” Ono said.

He praised then (and now) Japan head coach Eddie Jones, who spent the six months leading up to the World Cup building cohesion and trust amongst the playing and coaching groups.

Kosei Ono, raised in Christchurch, made 34 appearances for the Japanese national rugby side. Photo / Photosport

“We just knew what our strengths were and didn’t go too far away from that and that was playing with a lot of speed and moving the ball which seemed to work.”

Despite the mammoth upset, Japan were unable to make it out of pool play as South Africa and Scotland – who alongside Japan had three wins each – advanced to the quarter-finals.

“It would have been pretty cool to get to the next stage, which the next group were able to do in 2019 ... We did what we could do and put ourselves in a position to get through [but] we just didn’t have enough points in the end.”

The Springboks, meanwhile, were knocked out in the semifinal stage, losing 20-18 to the All Blacks, who went on to win the 2015 World Cup at Twickenham against Australia.