Springboks braced for 'ultimate test' in New Zealand
Both sides go into Saturday's game at Auckland's Mount Smart Stadium on the back of big wins in the opening round.
The Springboks thrashed Australia 43-12 in Pretoria last Saturday, the same day the All Blacks brushed Argentina aside 41-12 in Mendoza.
The winner in Auckland will put one hand on the trophy -- and fire a warning of intent for the World Cup.
The Rugby Championship has been reduced to three rounds because of the World Cup, which kicks off in September and will see South Africa defend their crown.
"I think it's going to be an epic match, both teams had a good performance last weekend," Smith told reporters.
"It's going to be a tough game."
The flanker expects a tight contest decided by "discipline and who is using their opportunities the most".
The Springboks have not lost in New Zealand since being routed 57-0 in Auckland in 2017.
They beat the All Blacks 36-34 in 2018, before the sides drew 16-all in 2019. Both those games were held in Wellington.
There is plenty of respect for the hosts from the Springboks camp.
"They are a good team, I wouldn't say they have a lot of weaknesses, if any," added Smith, who will start at blind-side flanker for Springboks captain Siya Kolisi, currently sidelined by injury.
"I think playing against the All Blacks is the ultimate test at the moment.
"The history and rivalry behind it is really big. That makes it such an iconic game."
Eden Park is unavailable as it prepares to host the opening match of the FIFA Women's World Cup, so the game will be at the home of the New Zealand Warriors rugby league team.
"It's a new place to play," Smith said of Mount Smart.
"But the class of rugby will still be the same. No matter where it's played, it's going to be a high-tempo game."
Smith is one of nine players in the starting South African team against New Zealand who were flown to Auckland a week early in preparation.
Centre Lukhanyo Am is among the six Springboks who also played Australia and retain their place.
"Coming from a game last week, I feel like I'm in good condition. We got here, recovered and started straight into it," Am told reporters.
"It's not an issue. We have done it multiple times over the seasons and New Zealand players as well.
"I think they went through similar conditions when they played away in Argentina."