The 2007 quarter finalists managed only one win apiece in the previous two World Cup campaigns but have been tipped as a genuine contender to make the knockout rounds in Japan.
The Wallabies were too strong for Fiji when they met in the pool stage four years ago but coach John McKee says his team has made massive progress since then.
"Our squad has probably been a bit more settled. Last time I came in just over a year out from the World Cup, so we were still working on our combinations going into the World Cup. I think this time we're much more stable around the team.
"We've got better depth across all positions - I think overall our squad is much stronger...but now it's time to put all of that into action in what we actually do and achieve in the games."
John McKee expects the Wallabies to stick with the up-tempo game that overwhelmed the All Blacks in Perth and says the Fijians will relish the chance to go toe to toe under the Sapporo Dome roof.
"It's amazing, it's absolutely perfect conditions to play rugby. Quite a number of our players play in France and they compare it to the Racing Metro stadium in Paris, where they play indoors also, but the difference here is we're on grass as well, which we prefer so it augurs for a great game of rugby because none of the elements can interfere."
"We will take our chances. Michael Cheika might think his team is unpredictable (but) I'd like to think we've got some unpredictability about us as well and I think with the type of players we've got in our outside backs but it's not just our outside backs, in amongst our forwards as well who can run in open space and offload and pass that given some opportunity I think we can put in some unpredictability in attack as well."
McKee believes Fiji can equal anyone in the world at set phase play, He was not surprised to see Australia name both David Pocock and Michael Hooper in their starting line-up and says whoever dominates at the breakdown will probably win the game.
"The contact zone, ruck zone, post tackle is going to be big indicators to the outcome of the game and for us it's important that we can be very effective in that area when we've got the ball to ensure that we can get continuity and get quick ball.
"It's been a big work-on for us through our campaign and the fact that those two are playing doesn't really make any difference to the work we've done, or we've had focused in that area because we know what a hotly contested area it will be."
The Fijians will probably need to beat Australia or Wales to have a shot at reaching the knockout rounds, but John McKee doesn't believe there's any added pressure riding on the outcome of today's match.
"Every game in the pool is important and I think that if we can win tomorrow, which we hope we can do, then it makes the win easier but it's not the end of the day either."