The Springboks have beefed up their scrum and put a halt to experimentation in an effort to overturn northern hemisphere champions Ireland on Saturday.
The World Cup holders won for the first time in four European tour matches with a 32-10 victory in Italy last weekend and reacted to the domination of its previously feared front five by moving captain John Smit back to his regular position of hooker.
Coach Peter de Villiers has been playing Smit at tighthead prop but saw his pack outplayed by France and then failing to dominate against Italy.
De Villiers has opted to start with props BJ Botha and Tendai Mtawarira and dropped Adriaan Strauss and Wian du Preez. World Cup-winner Victor Matfield replaces Andries Bekker at lock, while Schalk Burger is in at openside flanker and Danie Rossouw moves to No. 8.
The Springboks will need whatever ball they can win because Ireland have the players to capitalize on any possession that comes their way.
Jonathan Sexton scored 16 points on his debut against Fiji last weekend and has been given the chance to establish himself as first-choice flyhalf at Croke Park.
Ireland coach Declan Kidney decided to use the high-profile match, his team's last of the year, to test out Sexton against top-level opposition. He picked him ahead of Ronan O'Gara, the country's all-time leading scorer.
"I know we have a world-class outside half in Ronan but we have to find out things about ourselves," Kidney said. "Jonathan had a good game last week but with respect, Fiji were short of a few so it was difficult to read. I need to find out more."
O'Gara, who is sixth on the world all-time highest scorers list with 929 points, is on the bench in one of six changes from the team that beat Fiji 41-6.
Tommy Bowe returns on the right wing in place of Shane Horgan, Paddy Wallace comes in at inside center for Gordon D'Arcy and Tomas O'Leary is back at scrumhalf.
Loosehead prop Cian Healy is back after recovering from a shoulder injury, while lock Donncha O'Callaghan and openside flanker David Wallace also come in.
Healy starred on his debut in the 20-20 draw with Australia earlier this month but is likely to find things tougher against Botha.
"I don't think over the last year we've been shown up at the breakdown and maybe only against the All Blacks last year were we physically off the mark," fullback Rob Kearney said. "But since then I don't think we've been shy in wanting to bring that physical aspect to our game.
"This week is going to be as physical as it is ever going to be for us."
Ireland: Rob Kearney, Tommy Bowe, Brian O'Driscoll (captain), Paddy Wallace, Keith Earls, Jonathan Sexton, Tomas O'Leary; Cian Healy, Jerry Flannery, John Hayes, Donncha O'Callaghan, Paul O'Connell, Stephen Ferris, David Wallace, Jamie Heaslip.
Replacements: Sean Cronin, Tony Buckley, Leo Cullen, Denis Leamy, Peter Stringer, Ronan O'Gara, Gordon D'Arcy.
South Africa: Zane Kirchner, JP Pietersen, Jaque Fourie, Wynand Olivier, Bryan Habana, Morne Steyn, Fourie du Preez; Tendai Mtawarira, John Smit (captain), BJ Botha, Bakkies Botha, Victor Matfield, Heinrich Brussow, Schalk Burger, Danie Rossouw.
Replacements: Bismarck du Plessis, CJ van der Linde, Andries Bekker, Jean Deysel, Dewald Potgieter, Ruan Pienaar, Jean de Villiers.