Japanese fans celebrated their team’s shock Rugby World Cup win over heavily-favoured South Africa early on Sunday in a victory that is sure to give the sport a boost as the country prepares to host the event in four years.

The match started just before 1am local time and it was mostly diehard rugby fans who decided to stay up and watch. Many in Tokyo got the news when they woke up on Sunday morning.

Japan’s 34-32 win against the Springboks on Saturday was immediately regarded as the biggest upset in Rugby World Cup history.

“Japan gets historical win over South Africa with dramatic comeback,” read a headline on the Sports Hochi website.

Rugby has long been a niche sport in Japan where baseball and soccer dominate the headlines, but the win against the two-time world champions will vastly improve the sport’s profile.

A public viewing event was held at Ecopa Stadium in Shizuoka, which will host matches at the 2019 tournament but the win was so unexpected, it caught many off guard.

“I can’t believe it,” office worker Yuji Nakanishi said. “I didn’t see it but I’m going try to watch a re-broadcast tonight with some friends.”

Perhaps because of a reliance on foreign imports, Japan’s team has yet to catch on in the mainstream of the Japanese sports scene.

Karne Hesketh, who scored the winning try in Saturday’s win, was born in New Zealand as was the team’s captain Michael Leitch.

With preparations for the 2019 World Cup hitting some obstacles lately, the win over South Africa couldn’t have come at a better time.

World rugby officials were annoyed when it was announced that the new National Stadium, promised as part of Japan’s bid to host the 2019 event, won’t be ready in time.

The stadium, which is behind schedule and being built for the 2020 Tokyo Olympics, was to host the tournament’s showpiece games. It now looks like those games will be played in existing stadiums outside of central Tokyo.

The stadium switch even led to rumblings the event might be moved to another country, but Saturday’s win in Brighton should go a long way toward quashing those fears.

World Rugby has long coveted the Asian market and Japan is seen as the best hope to spread the sport’s popularity in the region, but it’s been a hard sell. Up until now, Japan’s only World Cup win was against Zimbabwe in 1991.

Japan’s next game is against Scotland and it’s a safe bet that many more will stay up this time to watch for themselves.