The Wallabies are like a "wounded animal" ahead of their high-stakes World Cup clash in Lyon, according to Wales assistant coach Jonathan Thomas.
Rocked by their first ever tournament defeat to Fiji, the Australians could make more unwanted history if they lose to Wales on Sunday (Monday AEST).
Eddie Jones's team could become the first Wallabies outfit to be eliminated at the World Cup's pool stage.
Thomas said that threat made Australia dangerous.
"We respect Australia as a rugby nation. They are a wounded animal, they can be dangerous," Thomas told reporters from Wales's Versailles base.
Australia hold a 5-2 lead across the countries' seven previous World Cup meetings, but Wales won the most recent encounter, a pool clash at the 2019 tournament in Japan.
Both teams advanced to the quarter-finals four years ago, with the Wallabies falling to England while Wales were knocked out by eventual champions South Africa in the semi-finals.
The Welsh are unbeaten in France from two games, holding off Fiji in a thriller before downing minnows Portugal last round.
Veteran Wales centre George North said taking maximum points from the opening two matches gave the team confidence ahead of the key clash with Australia.
He said securing a play-off berth on Sunday would be a "weight off the shoulders".
"I've been to quite a few World Cups now, and to get early results is good," North said.
"If you had said to us we would have 10 points after the first two games, everyone would have bitten your hand off.
"The Australia result against Fiji has put a spanner in the works for everyone, so it's a massive game for us and we have to go out and win it on Sunday.
"The boys are champing at the bit."
Wales flanker Tommy Reffell withdrew from the Portugal game in the warm-up and is no certainty to be available to face Australia.
