Mendoza - Argentina were forced into a late change for their Rugby Championship Test against Australia when midfield regular Jeronimo de la Fuente failed a fitness test on Friday, a day after hurting his left leg in training.
De La Fuente, who has started in every Pumas Test this year, was replaced by Santiago Gonzalez Iglesias, who will on Saturday make his first start in almost a year.
Three-time Rugby World Cup star Juan Martin Hernandez comes into the reserves for a match in which the Pumas are out to redeem themselves.
They are at risk of failing to earn a competition point for the first time since joining the competition in 2012.
The Pumas enjoyed one win in 2014, 2015 and 2016, against either Australia or South Africa, but have regressed this year with five heavy losses, none of them earning even a losing bonus point for being within seven points of the victor.
The Pumas pack has imposed itself only briefly, and the scrum was ruined last week by the All Blacks. The backline hasn't sparkled or threatened. And poor discipline has hurt them, highlighted by five yellow cards and one red.
Flank Pablo Matera insists the Pumas have the right game plan.
"We are failing to carry out the game plan," Matera said.
"The system is not failing, it is us players who are failing."
He added the team is more angry than disappointed with their results and how they are playing.
The nature of the competition means the Pumas don't have time to be frustrated, he added, but they also don't have time to fix all of their mistakes.
They remain determined to beat Australia, as they did in the same Malvinas Argentinas Stadium in 2014.
"If we beat Australia, we can finish the championship by beating a top team," Matera said.
"To beat Italy in November will not give us anything."
Kick-off is at 00:30 on Sunday (SA time).
Teams:
Argentina
15 Joaquin Tuculet, 14 Matias Moroni, 13 Matias Orlando, 12 Santiago Gonzalez Iglesias, 11 Emiliano Boffelli, 10 Nicolas Sanchez, 9 Martin Landajo, 8 Tomas Lezana, 7 Javier Ortega Desio, 6 Pablo Matera, 5 Matias Alemanno, 4 Marcos Kremer, 3 Nahuel Tetaz Chaparro, 2 Agustin Creevy (captain), 1 Lucas Noguera Paz
Substitutes:
16 Julian Montoya, 17 Santiago Garcia Botta, 18 Enrique Pieretto, 19
Banjamin Macome, 20 Leonardo Senatore, 21 Gonzalo Bertranou, 22 Juan Martin Hernandez, 23 Santiago Cordero
Australia
15 Israel Folau; 14 Marika Koroibete, 13 Tevita Kuridrani, 12 Kurtley Beale, 11 Reece Hodge; 10 Bernard Foley, 9 Will Genia; 8 Sean McMahon, 7 Michael Hooper (captain), 6 Jack Dempsey; 5 Adam Coleman, 4 Izack Rodda; 3 Sekope Kepu, 2 Tatafu Polota-Nau, 1 Scott Sio
Substitutes: 16 Stephen Moore, 17 Tetera Faulkner, 18 Allan Alaalatoa, 19 Rob Simmons, 20 Lukhan Tui, 21 Nick Phipps, 22 Samu Kerevi, 23 Henry Speight