The Japan wheelchair rugby team won its first world championship on Frida in an upset win against Rio de Janeiro Paralympic champion Australia.

World No. 4 Japan won the 2018 Wheelchair Rugby World Championship in a 62-61 nail-biter, which saw 27 turnovers and numerous big hits in the infamously rough sport.

The United States, the Rio silver medalists, won bronze at the 12-team meet.

Japan coach Kevin Orr said while the game was hard-fought, he was shocked by the Australian Steelers' game.

"I was really surprised how fragile they were," Orr told Kyodo News, saying the strength of Japan's supporting bench was key to its win.

Having suffered its only loss in the competition to Australia on Wednesday, Captain Yukinobu Ike said Japan's mental preparedness helped it pull through.

"There were countless times where Australia chased us down and I thought we were going to lose," the 38-year-old said.

"But we had prepared ourselves mentally, told ourselves we won't give up our lead, and will fight to the end. Everyone believed that and I think that was the key to our victory."

The Australians' loss was also keenly felt by the passionate supporters at Quaycentre Arena, who put the pressure on the Japanese side.

Ike said he is looking forward to the tables being turned, and playing in front of a home crowd at the 2020 Tokyo Paralympics.

"I hope that the people of Japan will support us and we're aiming to win another gold," added Ike.

Orr said the title of world champions provides "great momentum" for Japan heading into the 2019 Wheelchair Rugby Challenge, which will take place in Tokyo in October, and then the 2020 Paralympics.

"It's an exciting time to build wheelchair rugby (in Japan)," he said.

Friday was Japan's first gold medal match at a major international tournament, after taking home bronze at the 2016 Rio Paralympics and the 2010 World Championships.

Originally called "murderball," wheelchair rugby is a fast-paced and intense physical sport for quadriplegic athletes, combining elements of basketball, American football and ice hockey.

Male and female athletes compete together on a basketball-sized court and perform "tackles" by crashing their reinforced wheelchairs into opponents.