Francois Pienaar holds the William Webb Ellis trophy while being carried by teammate Hennie Le Roux after the Springboks won the rugby World Cup final in Johannesburg, South Africa on June 24, 1995. Photo: AFP

South Africa coach Jacques Nienaber is treating Saturday's rematch with Australia in Sydney as "a final" for his injury-ravaged side as they strive to stay in Rugby Championship contention.

The world champions started slowly and then failed to convert pressure into points against the Wallabies in Adelaide last weekend, crashing 25-17 for their second straight tournament defeat.

It left them propping up the table at the midway point with just one win from three games. Argentina surprisingly lead the way, with Australia a close second and the All Blacks third.

"This week is a final for us to stay in the competition and we are expecting Australia to be just as desperate, but so are we," said Nienaber.

"We let ourselves down in the last two games and we are determined to rectify that this week and change our fortunes in Australia."

The Springboks continue to search for a first win on Australian soil since 2013 and Nienaber has made eight changes to the starting lineup for the sold-out clash at Sydney's newly built Allianz Stadium, among them scrum-half Faf de Klerk.

Four are injury-enforced with influential fly-half Handre Pollard and center Lukhanyo Am among the casualties.

"It's always unfortunate to lose players in a squad but this opens the door for other players to step in and showcase what they can do in those positions," said the coach in a statement.

Damian Willemse moves from fullback to fly-half, with the experienced Jesse Kriel slotting in at center and talented young back Canan Moodie debuting on the right wing in a positional switch with Warrick Gelant, who moves to the bench.

Veteran Willie le Roux takes Willemse's place at fullback in his 77th Test, with the other backline change at scrumhalf, where Jaden Hendrikse replaces De Klerk. He was axed from the 23.

Prop Steven Kitshoff and hooker Malcolm Marx start in a new-look front row with Frans Malherbe. 

Jasper Wiese takes over at No.8 from veteran Duane Vermeulen, who is among the replacements.

AFP