Up to nine starters and four replacements will be desperate to impress South Africa coach Jacques Nienaber in a Rugby World Cup warm-up against Argentina in Buenos Aires on Saturday.

They have varying chances of making the 33-man squad of the title-holders for the global showpiece in France, that kicks off on September 8.

Nienaber will reveal his selections on Tuesday in Johannesburg, so the match at the 50,000-seat Estadio Jose Amalfitani offers a final chance to shine.

Backline starters needing to sparkle include winger Canan Moodie, inside centre Andre Esterhuizen and scrum-half Cobus Reinach.

Faf de Klerk, part of the 2019 team that defeated England in Japan to win the World Cup a record-equalling third time, is certain to be among the three France-bound scrum-halves.

That leaves Reinach, Herschel Jantjies, one of the Buenos Aires replacements, Jaden Hendrikse and injured Grant Williams fighting for two places.

Hendrikse is likely to be the only one of 42 World Cup hopefuls who will not have worn the green and gold this season after the match in the Argentine capital.

But Nienaber says the Sharks half-back renowned for his contestable box kicks is a strong contender for France as he recovers from the death of his father.

"We know what we have in Jaden. Do not misread the fact that he has not played this season. We wanted to give Cobus (Reinach) another go and Herschel (Jantjies) a go," said the coach.

Among the forward starters, there is a lot at stake for props Trevor Nyakane and Thomas du Toit, locks Jean Kleyn and Marvin Orie and flankers Franco Mostert and Deon Fourie.

- Value of versatility -

Both Nyakane and Du Toit could make it if Nienaber opts for six props, but there is likely to be room for only one of Orie or former Johannesburg-born Ireland forward Kleyn.

South Africa director of rugby Rassie Erasmus has stressed the value of versatility which could boost Fourie, a Test debutant last season at 35, as he is a former hooker.

Mostert is another utility forward, having been a lock, but competition in the back row is fierce with 10 hopefuls chasing a maximum of eight places.

Among those hoping to play off the bench, hooker Joseph Dweba, Jantjies, and loose forwards Jean-Luc du Preez and Evan Roos must star to have any hope of surviving the cut.

South Africa edged Argentina 22-21 last weekend in a match to decide second place behind New Zealand in a Rugby Championship reduced to three matchdays because of the World Cup.

The Springboks have made 13 changes to the starting line-up with only fly-half Manie Libbok and Orie starting against the Pumas on successive Saturdays.

Hooker Bongi Mbonambi will captain the team, becoming the second black player to lead South Africa in a Test after Siya Kolisi, who hopes to play later this month after recovering from a knee injury.

Argentina have changed five of the side that started a match in Johannesburg they would have won had fly-half Santiago Carreras not missed several kicks at goal.

Outstanding goal kicker Emiliano Boffelli, rested last weekend, returns on the right wing and reserve hooker Agustin Creevy is poised to win his 100th cap.

Others promoted to the starting line-up include full-back Martin Bogado, winger Santiago Cordero, scrum-half Gonzalo Bertranou and lock Pedro Rubiolo.