A crowd of over 60,000 is expected at the Principality Stadium for the third time in four weeks of a rollercoaster Autumn Nations Series for Pivac's men.
After conceding 55 points in defeat to New Zealand, Wales beat Argentina before falling to an embarrassing first-ever defeat to Georgia.
That result has put Pivac's future as Wales head coach under intense scrutiny, with his three-year reign having delivered just 13 wins from 33 starts.
With just 10 weeks until the Six Nations begins and less than a year till the World Cup, the Welsh rugby chiefs will have to make a swift decision on Pivac's future.
And the New Zealander is hoping a positive reaction against Australia will lift the mood in Cardiff.
"This week was a classic week of backs to the wall. We want to rectify last week's performance," said Pivac.
"The guys are really determined to finish off on a good note to give something back to the public who they feel, and we feel collectively as a group, that we let down last week, obviously.
"It is going to be two desperate teams coming together, but unfortunately there has to be a winner and a loser. We've got to make sure we do everything in our power to come out the right side."
Wales captain Justin Tipuric said defeat to Georgia will live with him forever as he hopes to bounce back from a week of sleepless nights.
"There are many sleepless nights," said Tipuric. "We don't go out there to play badly, and it was one of those performances that you are never going to forget in your life, unfortunately.
"You have to have that consistency to be up there with the best teams in the world and unfortunately we haven't nailed that at the moment."
Australia, also coached by a New Zealander in Dave Rennie, have problems of their own, with a raft of injuries following a 13-10 loss to Ireland in Dublin last weekend.
Defeat would condemn Australia to a 10th loss in 14 matches in 2022 and their worst calendar year since 1958, although this month's reverses against France and Italy were both a matter of a single point.
