Wales boss Mike Ruddock has been hampered by injuries to key players this autumn and has effectively had to build a new side without six British & Irish Lions, plus squad regulars Dafydd Jones and Hal Luscombe.
As a result, the performances have dropped and the results have ranged from a 41-3 thumping from New Zealand to a frustrating 11-10 win over Fiji and a defeat to South Africa that was perhaps not quite as comprehensive as the 33-16 scoreline suggests.
Ruddock concedes his side are behind where they were at this point last year, when heroic defeats to South Africa and New Zealand ultimately served as the perfect springboard for Grand Slam glory.
Thomas admits Wales have not matched up to his hopes and expectations - but they are still European champions and he is desperate to lead them to a first victory over Australia since the 1987 World Cup.
"It is important to us. I said at the start of this autumn series we want to put down a marker to show where we are against the top three teams in the world," Thomas said.
"At the moment I think that marker is further back than we want it to be. Australia are one of the top teams in the world so it is important we win.
"It will be the first time I have captained Wales against Australia and you have to respect them."
Just as the Wallabies respect Thomas, with coach Eddie Jones pin-pointing the Toulouse full-back as Wales' key attacking threat.
"Thomas is an inspirational player for Wales, and they generally play off the back of one of his runs," said Jones.
"Or if it's not Thomas, it's Shane Williams, and so those two guys are certainly ones we need to stop.
"Thomas has been improving as a player over the last three years and if he is not the most improved player in the world he is certainly close to it."
He has also proven a tough defender this year, both for the Lions and Wales, and he has reverted to his favoured full-back role for Saturday's game, with Matthew Watkins coming into the side at outside centre.
Thomas started in midfield to combat South Africa's more physical style last weekend, but Ruddock was anxious to move him back to the 15 jersey where he has been so effective both offensively and defensively.
"He has always performed superbly at full-back. As the last line of defence he has been spectacular. In fact, his all-round game has been spectacular," said Ruddock.