Warren Gatland's side went down to a 3-0 defeat on their summer tour to Australia earlier this year, albeit with the sides separated by just nine points over the three matches. And after defeats to Argentina, Samoa and New Zealand so far this month, Cuthbert says a win on Saturday would lift the squad.
"This week is a big test to see if we can put a performance in," said the Cardiff Blues wing.
"Beating a team like Australia would be superb for team confidence. We're all a really tight group and we hope we can put a performance in at the weekend. We just want to win."
Wales' performance in the second half against New Zealand, where they outscored the All Blacks by two tries to one, was a marked improvement on their recent form and Cuthbert wants more of the same on Saturday.
"We showed in that last 30-35 minutes against New Zealand what we can do," he added.
"That rugby was the best we have played in a while but we need to put in an 80 minute performance this time.
"I know people write Australia off but they're one of the best teams in the world so we need a 100 per cent performance and hope things go our way."
Wales head coach Warren Gatland has made four changes for Saturday's clash. Scott Andrews, Gethin Jenkins, Ian Evans and Aaron Shingler all start in the pack while the same backline who started against the All Blacks has been retained.
George North remains unavailable so Liam Williams, who impressed last week, again starts on the left wing.
"We need to pick up again where we left off in the second half last week," said Gatland.
"We managed to retain 73% possession after the break against the All Blacks and win the territory battle and we need to put Australia under similar pressure from the outset.
"We have played them regularly over the last couple of years and have come close to winning on a number of occasions but have not quite been able to get ourselves over the finish line.
"Both sides have had injuries to cope with, but there is every reason for optimism.
"The Millennium Stadium crowd will be in full voice again, they were outstanding last week and we are aiming to reach the end of a tough series on Saturday and finish off on a high."
Wales face an Australian side who have secured narrow wins over England and Italy in the last fortnight.
Head coach Robbie Deans welcomes back David Pocock who goes head-to-head with Wales captain Sam Warburton.
The change on the openside is one of three alterations from the Wallabies starting line-up which started in Florence last week.
The others see lock Kane Douglas return from a knee injury to take over from the suspended Sitaleki Timani while Tatafu Polota-Nau resumes at hooker.
"You don't win two Grand Slams in the last four years while also making the semi-finals of the Rugby World Cup without being a quality oufit," was Deans' view on Wales.
"If we were in their situation, I know the response I would be expecting.
"Cornered beasts are always the most dangerous - they have nowhere else to go but straight ahead."