South Africa have handed Jasper Wiese his first Test start and made three changes to their team to face the British and Irish Lions.
The second Test takes place in Cape Town on Saturday after the Lions came from behind to win the opener 22-17.
Hosts South Africa have brought in Wiese at number eight, while there are two changes to the front row as prop Steven Kitshoff steps in to win his 50th cap alongside the returning Frans Malherbe.
Kitshoff comes in for the injured Ox Nche and Trevor Nyakane drops to the bench to make space for Malherbe.
Leicester Tigers star Wiese was not even on the bench for first Test but he will come straight into the XV to replace Kwagga Smith.
Wiese has only previously made one substitute appearance at senior international level, which came in a warm-up match against Georgia this month.
Flanker Siya Kolisi will again captain the Springboks, whose coach Jacques Nienaber knows the stakes could not be higher.
"This is a massive game for us; it is do or die in order to stay in the race to win the series," Nienaber said as he discussed his team.
"We selected a team that offers continuity in selection, but also that we thought would be the best suited to achieve the objectives we have set for this match.
"Ox did well in the scrums last week and has been ruled out due to injury, but fortunately we have a world-class player in Steven who can step into the starting team.
"The fact that this will mark his 50th Test will make this occasion even more important for him.
"We disappointed ourselves last week, and we all know how important it is to bounce back with a strong performance and show our fighting spirit and pride as a team and nation."
Six of the eight Springboks replacements are forwards, with Herschel Jantjies and Damian Willemse the only backs on the bench.
Earlier on Tuesday, the Lions also announced three changes to their starting XV.
Warren Gatland picked Mako Vunipola, with Conor Murray and Chris Harris also coming into the team to face the world champions.
In the 13 series in British and Irish Lions history when the tourists have won the first Test, they have gone on to win 10, draw one and lose just twice.
It has happened in five such series against South Africa, leading to four wins and one draw.
Following their first Test win, the Lions are unbeaten in their last three Tests, their best run since a six-game spell spanning the 1971 and 1974 tours.
South Africa: Willie le Roux, Cheslin Kolbe, Lukhanyo Am, Damian de Allende, Makazole Mapimpi, Handre Pollard, Faf de Klerk; Steven Kitshoff, Bongi Mbonambi, Frans Malherbe, Eben Etzebeth, Franco Mostert, Siya Kolisi (captain), Pieter-Steph du Toit, Jasper Wiese.
Replacements: Malcolm Marx, Trevor Nyakane, Vincent Koch, Lood de Jager, Marco van Staden, Kwagga Smith, Herschel Jantjies, Damian Willemse.