It will be Ireland versus South Africa, north versus south, Jonathan Sexton versus Handre Pollard.
This is the main sub-plot to the first of three November internationals where the best fly-half in Europe will come face-to-face with the future of international rugby.
Team Manager Mick Kearney was able to confirm Sexton is "100 per cent" guaranteed to play following a slight tightening of his hamstring when playing for Racing Metro in France at the weekend.
"I don't think we were ever really concerned given that we knew he was going to play only a limited part in the game. He wasn't going to play 80 minutes," said Kearney.
"There is a little bit of tightness in his thigh. Obviously, if we felt he could do more damage to it, he wouldn't be played. The medical opinion is that he's fine to train today, for instance, and we don't have any concern about him at this stage."
Ireland will need their most important player at his brilliant best to counter the immediate impact of Pollard has made in The Rugby Championship.
South African coach Heyneke Meyer has already decided to build his future around the 2014 U20 World Player of the Year over the experience of Morne Steyn and Patrick Lambie.
On the face of it, they would appear more similar in style than not for their size and their all-round strengths.
Ireland scrum-half Conor Murray doesn't agree. "They are two different players," he said.
"Johnny is a bit older than him. He is a new player. He is playing with a lot of freedom, probably through his age. He is a dangerous player.
"South Africa have those qualities of huge men, big strong runners, really good set-piece. They also have an expansive game plan at the moment. I think that comes from him."
Pollard's natural game instincts give South Africa a layer of unpredictability, a where-is-he-going-next deception to their outlook that just isn't part of their DNA.
"They are willing to run from deep, try 50-50 plays, or the miracle plays. That just brings an extra threat to the South African team and that's definitely something we're looking at from Pollard."
And there you have it. South Africa have moulded a new way of playing based on what a 20-year-old teenager can bring to them.
Pollard is the difference, a game-breaker, heck, even a culture-changer for the once one-dimensional Springboks.