South Africa lead the series 2-1 which has been hit by scandal after the Australians cheated in the third test. At stake in the final test is the first post-apartheid home series win for the South Africans, and for the visitors, their integrity.
South Africa captain Faf du Plessis won the toss and elected to bat in the fourth and final test against a scandal-hit and much-changed Australia at the Wanderers in Johannesburg on Friday.
South Africa lead the series 2-1, having come back from losing the first test in Durban to win in both Port Elizabeth and Cape Town, where their 322-run victory was overshadowed by the ball-tampering scandal that has rocked the game.
Returning to action is likely to come as some relief to a beleaguered Australian side who have endured a week of high drama after their captain Steve Smith, his deputy David Warner and opener Cameron Bancroft were handed heavy bans and sent home this week for cheating in the third test in Cape Town.
The trio have been replaced by Joe Burns, Matt Renshaw and Pete Handscombe, while Tim Paine captains the side for the first time in a remarkable turnaround in prospects for a player not even considered by his state side a year ago.
Bowler Mitchell Starc, who has battled with injury, is replaced by debutant Chadd Sayers.
Burns and Renshaw only arrived in South Africa on the eve of the test.
South Africa are unchanged as they seek to clinch their first home series victory over Australia since apartheid-era 1970. It will be the final test for fast bowler Morne Morkel.
The storm that has followed the scandal has been widely felt in Australia and saw coach Darren Lehmann announce on Thursday that he was quitting at the end of the series.