Australia are the Paralympic kings of wheelchair rugby, but a shock loss to Denmark on Wednesday has jolted their chances of winning a third straight gold in the bone-juddering sport.
The Aussies, who had not lost a single game at the Paralympics since 2008, were stunned 54-53 by the debutant Danes in their tournament opener.
Only two teams from each of the two round-robin groups progress to the semi-finals, putting Australia's backs to the wall for their remaining matches against France and world champions Japan.
"I'm pretty devastated, to be honest -- I had never lost a game at the Paralympics ever," said Australia's Chris Bond.
"I don't know what to feel. All we can do is turn around and win the next two and make the semi-final."
Australia are the world's top-ranked team in wheelchair rugby -- originally known as "murderball" and famous for its high-impact, wince-inducing collisions.
They won gold at the 2016 Rio Games in dramatic fashion, edging the United States 59-58 after double overtime, in what is widely considered to be the best wheelchair rugby game ever.
They are led at the Tokyo Games by captain Ryley Batt, a ferocious competitor who is appearing at his fifth Paralympics and is known as the world's best player.
But the 32-year-old admitted he was off the pace against the Danes, with the Australians playing their first game in two years because of pandemic difficulties.
"You train as hard as you want at home, work hard every day as an individual, but coming together as a team is a different thing," said Batt.
"Working in pressure situations like that is totally different."
Batt was born with no legs, and underwent an operation to separate his fingers.
He says his father -- who competed in Ironman events -- encouraged him to fend for himself by making him crawl across the sand to get to the sea when they visited the beach.
He believes his parents' tough love helped mould him into the player he is today, and the Danish players got a close-up look at his fearsome talents.
- 'Toughest opponent' -
"He is the toughest opponent to play against," said Denmark's Mark Ingemann Peters.
"He's so agile, so fast. He is one difficult person to cover and play against. I have the utmost respect for him."
But Australia's shock defeat may have opened the door for other teams to come in and snatch their crown.
The US began their campaign with a routine 63-35 win over New Zealand earlier in the day, and star player Chuck Aoki said the Americans were gunning for the title.
"We got off to a good start today," he said.
"But we know that there are a lot of countries here that want it too, so we've got to show we want it more."
Aoki named Japan, Canada and Britain as potential rivals for the title, but said the memory of defeat in the 2016 final would make victory over Australia particularly sweet.
"The final in Rio has driven me every single day," he said.
"We were certainly disappointed and it was a great match, but every single day I wake up and say I want to get that gold medal. It's what's been driving me forward."
Batt and his Australian team-mates will do everything to try to stop that happening.
"Definitely confident we can win the gold," said Batt.
"I think you need times like this in sport. We've had some big losses in our career, but we've had some very successful Paralympic campaigns as well. We're going to wear this one."