But for the plans the Boks had for the blockbuster duel with the All Blacks at the Stade de France in Paris, it had to be done.
In the end, with the 7-1 split in favour of the forwards on the replacement bench, the decisions Nienaber made paid off and the Boks retained their world title, winning 12-11 in a final for the ages.
On Wednesday, after the Springboks landed in Johannesburg with the Webb Ellis Cup, Nienaber admitted leaving Libbok out for the final was tough on him.
‘It breaks your heart’
“It breaks your heart as a coach,” said the coach, who will be joining Irish side Leinster.
“That, for me, moving from an assistant coach to a head coach, is the worst part of the job – to tell players you are not selected.
“Manie is definitely ... No I can’t say that it will be the next coach that decides that, but I believe he has the ability to be the future (for the Springboks), if you think about how excellent he was.
“Him and Damian Willemse, since Handré (Pollard) got injured in Adelaide.”
Libbok rose to the occasion in the absence of double World Cup winner Pollard when the latter was injured and he led the Bok attack with distinction.
Yes, there were questions about his kicking ability but during the World Cup, he kicked some clutch conversions and penalties to prove his detractors wrong.
With the experience picked up in these pressure matches, he can only improve when faced with similar situations against top teams in the future.
Nienaber added the players who did not play in the final lost out because they opted for the 7-1 split and not that they weren’t good enough for the occasion.
7-1 was the way to go
“There are a lot of factors that we calculate when we do selections. And the analysis we did on New Zealand, we believed a 7-1 was the way to go ... and they had to miss out,” he said.
“But they took it like men and no egos. Yes, they were heartbroken – and they should be, because it’s such an honour and they were good enough to play in the final.
“As were André Esterhuizen and Canan Moodie, if you think about how they played against New Zealand the previous time.
“That is the beauty of this squad. Everybody was good from a performance level to play, but unfortunately, that is the way we make decisions.
“The players are big enough to take it like that.”
Nienaber explained that those who did not make the final 23 had the task of being the best version of the All Black players.
Reinach had to mimic Aaron Smith, Libbok had to be Richie Mo’unga, and the likes of Marvin Orie and Esterhuizen had big tasks too.
“They studied their mannerisms and their profiles. That is probably the beauty of this team. They get over it, and they have to fulfil another goal. In the previous two games, they had to start and lead the team to victory.
“Marvin played one-and-a-half games but he was Maro Itoje (of England), he worked Eben (Etzebeth) up. He was brilliant and fulfilled his role.”