Portugal Colonial - Wallabies vow to lift intensity against rampant Boks

Australia were thrashed 33-7 last week in Brisbane and left shell-shocked by the heft of the world champion Springboks, who particularly dominated at the scrum.

It was a reality check after Australia had won three straight matches against Wales and Georgia to kick-start new coach Joe Schmidt's tenure.

With thunderstorms and up to 40mm (1.6 inches) of rain forecast on Saturday, an uncompromising match is expected at Optus Stadium as attention focuses on Australia's battle of strength with the renowned bulk of South Africa.

"Something that the boys are ready for," Alaalatoa told reporters in Perth.

"Some of our boys, it was the first time playing them last week. (They'll) understand that feeling and understand where we need to be better.

"It's a great challenge, it was a tough learning for us after last weekend. We didn't execute the plan that we wanted, and technically we need to be better."

Australia made five changes for the match, with powerful winger Marika Koroibete to play his first Test since last year's World Cup, while loosehead prop Angus Bell returns from a foot injury.

"He's (Bell) a big body. We all know the talent that he is," Alaalatoa said.

"It's awesome to have him back. He's gone through a tough time in his rehab, but he's trained really hard."

The Wallabies will face a revamped South Africa, who made 10 changes, with only backs Cheslin Kolbe, Jesse Kriel and Sacha Feinberg-Mngomezulu, and forwards Elrigh Louw and Pieter-Steph du Toit retaining their starting places.

Regular skipper Siya Kolisi has been rested, with lock Salmaan Moerat captaining the team for the second time.

South Africa has prioritised rotating players and building depth ahead of the subsequent four Tests in the Rugby Championship against New Zealand and Argentina.

Coach Rassie Erasmus also has an eye towards the next World Cup in 2027 held in Australia.

But South Africa will still boast 14 World Cup-winning players for their first ever Test at the 60,000-seat Optus Stadium.

"That's a decision they want to make," Alaalatoa said. "For us, we've been deliberate and taken ownership of making sure we need to get better."

The Wallabies are expected to be fired-up in a determined bid to get back on track under hard taskmaster Schmidt, who took over from Eddie Jones after last year's disastrous World Cup campaign.

"For us as leaders, he (Schmidt) was pretty hard (on us) after the loss," Alaalatoa said. "The coaching staff has driven the fact that all the attention is back on us and just making sure that we continue to grow our own game.

"We know that we're not the finished product at the moment... We're building towards that."

C.Amaral--PC