Supporters of the Springboks will be hoping altitude plays a part in denting the All Blacks performance; especially in the second half.
But given the frequency of trips to and from the Republic during the Super Rugby season, all the All Blacks have become used to the travel and playing high above sea level.
A plus for the Boks, perhaps, is that before last month they had never before beaten the All Blacks at Wellington's Westpac Stadium. The did it with an inspired defence and an attack which made the most of every opportunity; something they couldn't do the test before against the Pumas in Argentina.
It was the first time the All Blacks had lost to the Boks at home since 2009 when they were beaten at Waikato Stadium.
The All Blacks will base themselves in Johannesburg this week before travelling by bus to Pretoria on the day of the game.
Boks at home against All Blacks (major grounds):
Newlands, Cape Town: 3 wins from 10 tests
Loftus Versfeld, Pretoria: 1 of 5
Ellis Park, Johannesburg: 9 of 14
Kings Park, Durban: 3 of 7
Free State Stadium, Bloemfontein: 1 win, 1 draw, 1 loss