Australia will enter Sunday night's Perth Test ranked No. 7, while world No. 1 South Africa remains favoured despite the Wallabies' home advantage.
New coach Les Kiss is shifting Joseph-Aukuso Suaalii from outside centre to winger.
Lock Jeremy Williams said Australia must confront the Springboks' forwards before unleashing Suaalii, Max Jorgensen and Harry Potter.
"You're fully aware that it's going to be a physical game, and it's going to be won up front," Williams said.
"We've been training (for) that this week. We know what's coming."
South Africa's side still includes World Cup winners, despite only Eben Etzebeth and Ethan Hooker retaining starting places from the team that beat New Zealand 43-28.
Etzebeth has 146 Test caps, Franco Mostert 84, while Herschel Jantjies and Handre Pollard return from injury.
"They've obviously named quite an experienced team. In the locks they've got (230) caps between them," Williams said.
South Africa won 30-12 in Perth in 2024, but Australia recovered from 22-0 down to win 38-22 in Johannesburg last year.
"We're really pumped to get out there and put in a good performance," Williams said.