Waratahs coach Dan McKellar said on Thursday that beating the British and Irish Lions was "doable", but admitted the scale of the challenge for his under-strength team was daunting.
The chances of an upset in Sydney appear slim, with the tourists racking up 16 tries and 106 points across their opening two tour wins against the Western Force and Reds.
"We are not playing Super Rugby or anything else. We are playing a high-quality test team. But they’ve got two arms and two legs, and you just have to put them under pressure," McKellar said.
"The Force and the Reds, they have done that... being able to do it and sustain it for long periods of time is the challenge.
"But as has been proven in the past, it's certainly doable. You just have to be very good."
While wing Andrew Kellaway and prop Taniela Tupou have been released from Australia's training camp for the match, the Waratahs are without several key players who remain with the Wallabies ahead of a test on Sunday against Fiji.
They include dynamic wing Joseph Suallii, scrumhalf Jake Gordon, prop Angus Bell and hooker David Porecki.
McKellar said set-piece dominance could be a key weapon for the Waratahs.
"Dominant set-piece is a big part of what we do," he said.
"Ideally, we can get dominance at scrum time, because off the back of that, you get field position, you are in the penalty count, and you game just flows from there.
"We've worked incredibly hard over the last month since Super Rugby finished for us," he added.
"I want to see a transfer of that and put a performance on that we can hang our hat on."
Long-serving back-row forward Hugh Sinclair will captain the side in what will be the last game of his professional career.
One-test Wallaby wing Darby Lancaster is included, while former Australia lock Matt Philip will make his Waratahs debut from the bench after returning from a stint in Japan.
