Flyhalves Handre Pollard of South Africa and Tomas Albornoz of Argentina have received rave reviews ahead of crucial Rugby Championship second-round matches on Saturday.
Both countries suffered home losses, to Australia and New Zealand, last weekend and dare not lose again if they hope to be contenders for the southern hemisphere title.
Reigning world champions South Africa were stunned 38-22 by Australia in a remarkable match that delivered a first Wallaby triumph in Johannesburg for 62 years.
Argentina reduced a 31-10 halftime deficit against New Zealand to seven points before All Blacks substitute hooker Samisoni Taukei'aho powered over the tryline twice for a 41-24 victory in Cordoba.
This weekend, Cape Town hosts the Springboks and the Wallabies while the Pumas and All Blacks clash again, this time in Buenos Aires.
The results impacted the world rankings with New Zealand rising one place to first, South Africa slipping two spots to third behind Ireland, and Australia and Argentina remaining sixth and seventh.
Double World Cup winner Pollard replaces Manie Libbok in one of 10 changes to the team that built a 22-point lead over Australia within 20 minutes before collapsing in the second half.
Springbok legend Victor Matfield told a podcast the outcome in Johannesburg could have been different had Pollard been on the bench.
"Not having him among the replacements was a mistake. Your best players, like Handre, must always be involved in the big games," said the lock who made 127 test appearances for the Springboks.
"We are not so far ahead of everyone else that we can take these chances in big test matches, we need our best players out there."
Matfield believes Pollard, whose goal-kicking was crucial in the 2019 and 2023 World Cup triumphs, will bring vital calmness as defending champions South Africa face a must-win encounter.
A broken jaw has ruled Johannesburg try scorer Dylan Pietsch out of the rematch, and debutant Corey Toole, labelled the fastest man in Australian rugby, takes his place on the left wing.
SUPERSTAR
Both teams have been hard hit by injuries and among the absentees in Cape Town will be the rival captains and try scorers last weekend, loose forwards Siya Kolisi and Harry Wilson.
Stephen Donald, the flyhalf who came off the bench to help hosts New Zealand beat France in the 2011 World Cup final, told a separate podcast that Albornoz could become a rugby superstar.
"He was mightily impressive," he said, referring to Albornoz, whose performance included scoring a try, kicking three conversions and a penalty to become the early leading Champioship points scorer.
"His kicking game was absolutely outstanding. As the game wore on, his confidence started to really lift up and we saw a bit of pace from him."
'A GREAT ALL BLACK'
While Albornoz will try to mastermind a first victory for the Pumas over the All Blacks in Argentina, the rematch will be a special occasion for New Zealand hooker Codie Taylor.
The 34-year-old will win his 100th cap for the nine-time Rugby Championship winners, and coach Scott Robertson hailed the front rower as "a great All Black".
"The way he carries himself and the example he sets are testament to him as a person, and he will front this week in the same way he has for the past 99 tests."
It will also be a day to remember for No 8 Simon Parker, who wins his first cap in a back row completed by Ardie Savea and Tupou Vaa'i.
"(Simon has) earned his selection through performance and consistency. He is a big physical man, and he is ready to make an impact," said Robertson.
The New Zealand bench includes prop Tamaiti Williams and loose forward Wallace Sititi, who are available after recovering from knee and ankle injuries, respectively.
Captain and hooker Julian Montoya pinpointed a problem facing the Pumas: "Many of our mistakes were made in the final minutes of each half (in Cordoba). Those minutes are where we have to do better."