He said from 2018, his coaching team felt they could win the 2023 World Cup, and their 2019 success was something that happened along the way, so it was a relief they were good enough to win consecutive Cups.
Nienaber paid tribute to his 33-man squad and especially first five-eighths Manie Libbok and Cobus Reinach, who were left out of the final after big contributions earlier in the tournament but who accepted the management strategy preferred for the game.
"They probably deserved to play this match. I'm not saying we are geniuses, we don't try to be creative and think out of the box, it is just the squad we have, the depth we have, how close the players are."
Nienaber said he went into the game not wanting to have injuries to hooker Bongi Mbonambi or halfback Faf de Klerk. But Mbonambi's replacement, prop Deon Fourie, covered himself in glory with his lineout throwing and tackling.
"At whatever age he is – 37 – to put in a shift like that is special. I have coached Deon since he was 20 years old and I always knew he had that dog in him."
Nienaber added that All Blacks coach Ian Foster was one of the only coaches he knew of those South Africa played against.
"He's the only guy I ever have conversations with. That speaks to the kind of person he is.
"Before the warm-up game at Twickenham, there was a cocktail function a day or two before where I, my wife, and he were chatting away for 40 minutes about life and family.
"I am happy for us, but my heart breaks for him because I know what he feels like. He is an exceptional human being and an unbelievable coach. He has been written off numerous times, but the quality team the All Blacks are, they find a way.
"If you look at sports teams in the world, all of them, they are probably one of the most successful teams, they always have been. He is a leader of that and he is a quality individual."
Nienaber said defence was his area of concern in the team, and he was delighted flanker Pieter-Steph du Toit produced a 'phenomenal' performance.
"He put himself in the right positions...He was like a machine."
Captain Siya Kolisi said when rival captain Sam Cane was red-carded, he knew the All Blacks would lift as they did.
Kolisi admitted to being nervous while the tackle that saw him sin-binned was reviewed, but he believed he made the proper movement to avoid an upgrade to red.