A bonus-point victory at London’s Olympic Stadium (kickoff 1545 GMT) would see the Springboks top the pool and go some way to banishing the disappointment of the 34-32 loss to Japan that shook the game to its very foundations.
Subsequent victories over Samoa and Scotland have given them momentum as the quarter-finals loom and they have a final hurdle in a U.S. team that is physical and full of energy but should lack the skill-set to unduly trouble the Springboks.
Most, of course, would have said the same of Japan or even Argentina, who claimed a first ever victory over South Africa in Durban in August after another below-par performance from Heyneke Meyer’s side.
And that will be the nagging doubt for the coach going into this fixture – the knowledge that his team have the unhappy knack of wilting when they should be winning.
“They will be up for this match against us, waiting for us. I watched their last game against Scotland and it was immensely physical,” Meyer said of the Americans.
“We have to be humble, keep our feet on the ground and realise it will be another tough scrap.”
The Boks can do physical, that has always been right up their street, meeting fire with fire.
Japan, however, brought speed of thought and motion to their game, seemed quicker to every ball, and it was there where the Boks struggled.
U.S. coach Mike Tolkin has made 12 changes to the side that lost 39-16 to Scotland last time out.
Seven players will be featuring in the tournament for the first time, with only hooker Phil Thiel, loose-forward Samu Manoa and wing Blaine Scully retaining their places in the starting line-up.
There will be a first World Cup appearance for South African-born scrumhalf Niku Kruger, who only made his USA debut last month.
“It comes to a point in this tournament with a four-day rest where you have to use the whole squad,” Tolkin told reporters.
“Every team that’s been in this situation has had to do the same thing. We have to use the full squad and we’re confident in this full squad.”
Teams: South Africa: 1-Tendai Mtawarira, 2-Bismarck du Plessis, 3-Frans Malherbe, 4-Eben Etzebeth, 5-Lood de Jager, 6-Francois Louw, 7-Schalk Burger, 8-Duane Vermeulen, 9-Fourie du Preez (captain), 10-Handre Pollard, 11-Lwazi Mvovo, 12-Damian de Allende, 13-Jesse Kriel, 14-Bryan Habana, 15-Willie le Roux. Replacements: 16-Schalk Brits, 17-Trevor Nyakane, 18-Coenie Oosthuizen, 19-Pieter-Steph du Toit, 20-Willem Alberts, 21-Rudy Paige, 22-Morne Steyn, 23-Jan Serfontein. United States: 1-Oli Kilifi, 2-Phil Thiel, 3-Chris Baumann, 4-Louis Stanfill, 5-Matthew Trouville, 6-Danny Barrett, 7-John Quill, 8-Samu Manoa (captain), 9-Niku Kruger, 10-Shalom Suniula, 11-Zach Test, 12-Andrew Suniula, 13-Folau Niua, 14-Brett Thompson, 15-Blaine Scully.
Replacements: 16-Joe Taufetee, 17-Zach Fenoglio, 18-Mate Moeakiola, 19-Titi Lamositele, 20-Cam Dolan, 21-Al McFarland, 22-Mike Petri, 23-Chris Wyles. Referee: Pascal Gauzere (France)
(Editing by Nick Mulvenney)