And the Ireland skipper is certain that there are plenty of candidates to assume the reins whenever the hugely successful head man eventually leaves.

Schmidt, currently under contract through to the end of next year's Rugby World Cup in Japan, has promised that he will make a decision on his future by the end of this year. He has been in Ireland now for the last eight years.

Trophies have piled in to the IRFU's HQ on Lansdowne Road since he took over in 2013, following on it itself from a hugely successful stint down the road with Leinster where he took over from Michael Cheika in 2010.

“What Joe has done for Irish rugby, not just the national team but Leinster, is evident and plain to see in the silverware,” said Best ahead of Saturday's meeting with Argentina at the Aviva Stadium. “It speaks for itself.

No matter what Joe does, he has changed Irish rugby, how we perceive performance and our preparation. His legacy will obviously be silverware and what Leinster have now become and what Ireland are pushing towards becoming and have achieved.

“It will also be about the coaches that he eventually brings through in years to come. We maybe see a bit of it now with Paulie (O'Connell) over in Stade (Francais) but you will probably start to see that more when guys who have had five, six or seven, ten, years involved with him starting to retire and take up that side of the game.

“That will probably be the lasting legacy.”

Schmidt has already invited Ronan O'Gara, Felix Jones and Girvan Dempsey into the inner circle in the past when bringing them on a summer tour of the USA and Japan in 2017. And he has a world-class team of assistants already around him.

Andy Farrell has been drafted in with some success on the back of his stint as defence coach under Stuart Lancaster with England while Simon Easterby was persuaded to call time on a head coach role with Scarlets in Wales.

Add in the highly-respected scrum coach Greg Feek and skills coach Richie Murphy and the management group assembled by the New Zealander is hard to fault.

And, should Schmidt decide to call time in the coming weeks then Best is confident that the baton will be picked up.

When you look at our coaching staff there is that option, massively. Those guys take (on) a lot, Simon and Faz took a lot of the preparation last week (for the Italy game in Chicago) and you saw what happened there.

“Simon has obviously been a head coach at Scarlets. Faz has coached at Saracens who aren't bad. He has coached with England and he has been a massive part of our success here. So there is plenty of options and plenty of good young coaches around.

“That is the next big step, not just for Ireland but for the provinces, to bring through Irish coaches and not have an over-reliance on foreign coaches because there are plenty there. We've just got to bring them through the pathways and let them flourish.”