Fiji are expected to enter the Saint-Etienne match on Sunday (Monday AEST) breathing fire after they fell short against Wales in their opening pool game.
The Fijians rallied from a 32-14 deficit, scoring twice in the last seven minutes before former NRL star Semi Radradra knocked on close to the line in the dying seconds, condemning his team to a 32-26 loss.
The Wallabies, meanwhile, had an easier time in their tournament opener, banking a 20-point win over Georgia to sit top of pool C, with two teams moving through to the quarter-finals at the end of the preliminary phase.
“It was a great game to watch right until the last minute. It was very exciting,” said Wallabies winger Mark Nawaqanitawase.
“Fiji showed that flair, I think they ran 1000 metres during the game. Credit to Wales, they defended well and managed to get the win.”
Barring any upsets through the pool stage, those results mean Fiji must beat Australia to clinch a play-off spot.
Putting the Australians on notice, Fiji totalled 1106 run metres in Bordeaux, forcing the Welsh to make a staggering 237 tackles.
Radradra, who played 94 games and scored 82 tries in the NRL for Parramatta before switching codes in 2017, topped the tally with 160m.
The athletic Nawaqanitawase, who has been likened to former Wallabies fullback Israel Folau for his skill in the air, led the Wallabies' charge with 143m from his 13 carries.
He acknowledged his team would need to stiffen their defence after the Georgians found some gaping holes, particularly in the outside channels.
"It shows how much the Fijians are carrying the ball, so credit to Wales, they defended well and we managed to get the win," said Nawaqanitawase.
"I think any team coming up against Fiji is going to have to tighten up a few things.
"We've had that game and we've got to fix up a few things and obviously each game we want to improve.
"We'll want to tighten up and make sure that we're connected because they're going to bring a lot of mystery. They can do anything out of nothing so we've just got to make sure we're connected and ready for a couple of things."