The Springboks have twice before chosen seven black starters, against France in Durban two years ago and against Wales in Washington last season.
An agreement reached several years ago between the government and rugby officials says that 50 percent of the 31-man squad for the Rugby World Cup in Japan this year should be black.
In the apartheid era, rugby was racially segregated with blacks barred from representing the Springboks.
Progress towards a team more reflective of a 92 percent black population in the republic has been slow since the collapse of apartheid almost three decades ago.
The 1995 World Cup-winning team had only one black, winger Chester Williams, and the 2007 champions just two, wingers JP Pietersen and Bryan Habana.
Full-back Warrick Gelant, wingers Sibusiso Nkosi and Makazole Mapimpi, fly-half Elton Jantjies and scrum-half Herschel Jantjies are the five blacks in the backline.
An all-black front row of Tendai 'The Beast' Mtawarira, Bongi Mbonambi and Trevor Nyakane brings the number of black starters to eight.
There are also three blacks -- winger Dillyn Leyds, prop Lizo Gqoboka and lock Marvin Orie -- on the bench.
Herschel Jantjies, the 'find' of the Super Rugby season among the four South African sides, and Toulouse flanker Rynhardt Elstadt will win first caps when they face the Wallabies.
Gqoboka is the third uncapped player in an experimental matchday 23 that will be led by lock Eben Etzebeth as regular skipper and flanker Siya Kolisi is injured.
The team shows 13 changes from that beaten by Wales in Cardiff last November in their previous outing with only centre Jesse Kriel and flanker Pieter-Steph du Toit retained.
"I want to congratulate Rynhardt, Herschel and Lizo on their first inclusions in a Springbok matchday squad," said coach and former Springbok loose forward Rassie Erasmus.
"We have planned to mix things up in the first two Tests of the season, in order to give game time to as many of the players in our wider squad.
"This is the right combination to face a very good and competitive Australian side so we are in for a great contest."
The Rugby Championship, usually a two-round competition also involving Argentina and New Zealand, has been shortened to one round because the Rugby World Cup kicks off on September 20.
South Africa (15-1)
Warrick Gelant; Sibusiso Nkosi, Jesse Kriel, Andre Esterhuizen, Makazole Mapimpi; Elton Jantjies, Herschel Jantjies; Francois Louw, Pieter-Steph du Toit, Rynhardt Elstadt; Lood de Jager, Eben Etzebeth (capt); Trevor Nyakane, Bongi Mbonambi, Tendai Mtawarira
Replacements: Schalk Brits, Lizo Gqoboka, Vincent Koch, Marvin Orie, Marcell Coetzee, Cobus Reinach, Francois Steyn, Dillyn Leyds
Coach: Rassie Erasmus (RSA)