The Pumas are hoping to bounce back at Twickenham on Saturday after last weekend's 67-30 defeat in Durban.
Coach Felipe Contepomi made three changes to his pack and four among the backs, including handing only a second cap to 26-year-old Geronimo Prisciantelli, for a match in which South Africa will retain the title with a bonus-point victory.
He comes in at flyhalf and is paired with Simon Benitez Cruz, who replaces Gonzalo Garcia after he was taken off on a stretcher with concussion last Saturday and ruled out of the last clash of the championship.
Prisciantelli's selection sees Santiago Carreras moved to fullback, with Juan Cruz Mallia switched from No.15 to the left wing in place of Mateo Carreras.
Justo Piccardo replaces Lucio Cinti at centre, and Bautista Delguy comes in for Rodrigo Isgro on the right wing.
Contepomi has switched back to the lock pairing that started last month's victory over Australia in Sydney, choosing Guido Petti and Pedro Rubiolo ahead of Franco Molina and Lucas Paulos.
Joaquin Oviedo has been replaced by Santiago Grondona at the back of the scrum.
The bench will continue with a six-two forward split as Contepomi expects another physical battle with the Boks.
Of the seven changes, Contepomi said: "These guys have been training with us all the time. Some of them have played before in some of the other games, and now they will feel that they are ready.
"They've got good energy, they are up for the challenge, and mentally, physically and technically they are ready for it.
"Hopefully we are up to standard and we can give a good performance and be up there to be competitive against the best team in the world.''
However, the coach said the Pumas needed to be better under the high ball, at set pieces and in direct play.
The match will mark the 52nd time Julian Montoya captains Argentina, setting a record for the country.
South Africa will successfully defend the title with a bonus-point victory at Twickenham no matter what happens in the other match in Perth between Australia and New Zealand.
A victory without a bonus-point will likely also be enough given their vastly superior points difference over the second-placed All Blacks.
ARGENTINA:
15-Santiago Carreras, 14-Bautista Delguy, 13-Justo Piccardo, 12-Santiago Chocobares, 11-Juan Cruz Mallia, 10-Geronimo Prisciantelli, 9-Simon Benitez Cruz, 8-Santiago Grondona, 7-Marcos Kremer, 6-Pablo Matera, 5-Pedro Rubiolo, 4-Guido Petti, 3-Joel Sclavi, 2-Julian Montoya (captain), 1-Mayco Vivas
Replacements: 16-Ignacio Ruiz, 17-Boris Wenger, 18-Francisco Coria Marchetti, 19-Franco Molina, 20-Juan Martin Gonzalez, 21-Joaquin Oviedo, 22-Agustin Moyano, 23- Rodrigo Isgro
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