The world champion Springboks are seeking a fifth successive win against the Wallabies as they also seek to retain their southern hemisphere crown won last year.
Scrumhalf Grant Williams is alongside flyhalf Manie Libbok, with battering ram Andre Esterhuizen at inside centre and Jesse Kriel in the number 13 jersey.
The back three comprises fullback Aphelele Fassi, with Kurt-Lee Arendse and Edwill van der Merwe on the wing.
Kolisi switches to No.8 having played much of the recent United Rugby Championship season there for the Sharks, with Marco van Staden and Pieter-Steph du Toit the two flankers.
Coach Rassie Erasmus said it was a backrow selected with a ferocious breakdown battle in mind as the Wallabies contest hard in that area.
Veterans Eben Etzebeth and Lood de Jager are the lock pairing, while hooker Malcolm Marx has props Ox Nche and Wilco Louw either side of him.
"We've been experimenting with player combinations during the (July internationals) and at our conditioning camp in the last two weeks, and we believe this team will allow us to play the type of rugby we want to play against Australia," Erasmus said.
"All of the starters except for Edwill have faced them before, and we are confident that he is ready for this challenge."
Centre Damian De Allende is sidelined through injury and wing Cheslin Kolbe was not selected as a precaution despite returning to training last week.
Erasmus, who switched his team announcement to Monday, opted for a 5-3 bench split between forwards and backs rather than 6-2, in a sign the Springboks intend to run the ball.
Scrumhalf Cobus Reinach, wing/centre Canan Moodie and utility back Damian Willemse are the three backline options.
"They (Australia) are a physical and well-coached team, and we'll certainly not underestimate how much those performances (against the British & Irish Lions), combined with their motivation to bounce back strongly against us after the last few results between the teams, and win their first match ever at Ellis Park, will inspire them," Erasmus said.
South Africa team:
15–Aphelele Fassi, 14–Edwill van der Merwe, 13–Jesse Kriel, 12–Andre Esterhuizen, 11–Kurt-Lee Arendse, 10–Manie Libbok, 9–Grant Williams, 8–Siya Kolisi, 7–Pieter-Steph du Toit, 6–Marco van Staden, 5–Lood de Jager, 4–Eben Etzebeth, 3–Wilco Louw, 2–Malcolm Marx, 1–Ox Nche
Replacements: 16–Bongi Mbonambi, 17–Jan-Hendrik Wessels, 18–Asenathi Ntlabakanye, 19–Franco Mostert, 20–Kwagga Smith, 21–Cobus Reinach, 22–Canan Moodie, 23–Damian Willemse.
