South Africa, the first side to win four World Cups, held off a 14-man All Blacks side in a gruelling battle that forced them to dig deep and left both sides out on their feet.
"I think the main thing was just the strength of the squad," the coach said.
"They’re experienced, they've been in a World Cup final before, some of them were playing a third World Cup. So I think the experience just pulled it through, they’re an amazing bunch of guys, all warriors.
"We’ve come a long way with these players, we’ve planned for this since 2018," added Nienaber, who is leaving for a job in Ireland after the tournament in France.
It was a victory by the slimmest of margins against their traditional rivals who fought back despite a numerical disadvantage.
"The All Blacks took us to a dark place, it just shows what team they are, they fought, they put us under so much pressure," said Springbok captain Siya Kolisi.
"Credit to my boys for the fight, I’m just grateful."
South Africa also had their setbacks.
"We lost our hooker (Bongi Mbonambi) in the early part of the game and obviously we had to adjust to that.
"The All Blacks put us under so much pressure in lineouts, but somehow we found a way."
Kolisi said the impact of victory in South Africa, struggling amid economic strain, high levels of unemployment, criminality and corruption, would be a much-needed tonic.
"People who are not from South Africa don’t understand what this means for our country. This is not just about the game, our country goes through such a lot. We are the very hope that they have," he said.
Flanker Pieter-Steph du Toit, who made 27 tackles in the game, was named man of the match
"I guess as a team we like the drama,” he quipped.
"We’ve had a lot of drama over the last years, so I supposed we are used it. It shows the resilience of the team… and the whole of South Africa as well.
"The last three games were really rough, each one we played like a final. Each one we won by one point, so it was quite tough for us," he said with a touch of understatement.
