"It is probably my last Test – it is my last Test match that I will be the head coach," he informed media after the side's Thursday training run.
He signed a six-year deal in 2018 to be the director of rugby for South Africa. Because of the fall out after the disappointing run of results under previous coach Allister Coetzee, Erasmus took on the coaching role in a bid to have the Springboks competitive for the World Cup.
After Saturday's final he will step down to do his director of rugby role.
"For me, it's an emotional [game] in the sense that I didn't think 25 Test matches would go that quickly," he said.
When earlier taking on the Munster coaching role from which he returned in 2018, it was while doing things with his family and sharing the last four or five years while his children were still at school.
"The moment you get hands-on with the Springboks again, the adrenaline starts pumping again…it is a totally different feeling, and I am enjoying it thoroughly now.
"It's wonderful to be here. It's sad that it's only three days, and then it is all over," Erasmus said.
However, he said he would still be heavily involved in future campaigns, whichever way it worked out with a new head coach.
"Me being involved again gives me such hope for what rugby can do for South Africa.
"I was one of those guys three years ago who said, 'Let's just play, boys, let's just play. Stop talking about this hope thing, because everybody is about it. Rugby is rugby, and let's just play'.
"But I've totally changed my mind. I believe if we play that right way, and with the passion, and the people can see it, it just helps people forget about their problems, and agree with things.
"I have enjoyed it thoroughly, and whatever happens on Saturday, we have to make sure we use this for the next four, five, six, seven years and that it doesn't get lost again," he said.