Mackay will have other ideas as he chases a historic first-ever European place with County after guiding the Highlanders into the top six against the odds in his first season in charge.
Postecoglou has already claimed titles in Australia and Japan, and Mackay, part of the Celtic team that won the title in 1997-98 and stopped Rangers clinching 10-in-a-row, thinks that will stand him and his players in good stead.
“It will help hugely – he is someone who has been there, seen it, done it. That will help his players," Mackay said.
“He’s probably still coming to the biggest pressured situation he’s been in, just from the fact of what that club is as an institution.
“And he is playing against an institution in terms of what last Sunday at Hampden looked like.
“He knows every day as he walks around wherever in Glasgow he lives – 10 times a day someone wants to shout over and say hello.
“It is different being at those two clubs, a different way of life. To actually be the main man, the guy who stands in those shoes… I spoke to someone about this the other day.
“It is one of the presentations I do on the pro-licence.
“Being a coach or a manager and actually understanding what it takes to be in those shoes.
“In that job, at that club? To stand in those shoes takes something not many people understand because of the pressures on you from fans, players, staff, board, and public. And it is the same at Rangers.”
Mackay has also been impressed with the way Postecoglou has handled himself in Glasgow, having recovered from a rocky start to his Parkhead career.
“He is very focused and driven. He’s very respectful, I have to say, when I’ve met him and chatted.
“We don’t know each other but this season we’ve had a few texts. What I’m seeing is someone very driven, quietly confident in his own ability.
“From what I hear, he is quite quiet about the place but he has recruited very well. Clearly it is his recruitment.
“He has been in Japan and it is Japanese players who have come in, with two or three others.
“He clearly has a way he wants to play and has a body of work behind him as well.
“There is his Australian work and then he’s gone to Japan and got Japanese work.
“He’s been part of The City Group which brings something else with it and has had the confidence to walk into that cauldron there in Glasgow and, losing three of your first six of the season, anything can happen. That resilience under fire – any time I see his press conferences, even at the start of the season, it is nice and calm from him.
“He didn’t let it get to him too much and that’s because he’s an experienced manager and has been through a lot of it before.”