Neil Lennon has revealed how Sir Alex Ferguson's advice has helped shape Celtic's Champions League run which continues with the visit of Juventus on Tuesday.
Former Premier League midfielder Lennon is in his third season in charge at Celtic Park, and has navigated his side's passage to the last 16 of the European competition by beating Barcelona to qualify ahead of Benfica and Spartak Moscow.
They are now bidding to become the first Scottish side to reach the quarter-finals since the competition became the Champions League in 1992, something which Manchester United boss Ferguson has been keen to help them achieve.
He told the Sun: "When we won the league last season, Sir Alex wrote me a letter. He congratulated me and I thought that was nice. It was a bit of class. I rang him and asked was there any way the backroom staff and I could come down to Manchester and have a look at Carrington.
"He said 'We are renovating the training ground at the minute but I will come up and see you'.
"He came up one Sunday while he was visiting family up here. He came in and sat with us for two hours in the coaches' room.
"It was brilliant. We just talked football. His knowledge is incredible and he has kept in touch ever since.
"He came up to one of our games a couple of weeks ago. He has been a port of call for me. Particularly in the Champions League. We were mainly playing on the same nights and he was wishing me luck but also giving me a wee titbit on who we were playing.
"His advice to me was to go with your gut instincts. Managers have to make decisions whether they are the right ones or wrong ones. He said you cannot have a player bigger than the manager, especially at Celtic or Manchester United.
"We talked about his dark days. I asked about how he got over his defeats. I am more interested in that. Winning is winning. What you do when you win is reflect on it for a few hours and then start preparing for the next one.
"If you lose, then it annoys the life out of you. You question yourself. You question your team selection. You have anger with the players.
"I asked him how you get over that. He said 'Deal with it on the day. Deal with the players there and then and move on'.
"To be fair I think he is very good with a lot of managers, not only me. He has helped a lot of people in the game and a lot of that gets missed.
"I am three years into this and it is really demanding. He has had 20-odd years at it. It is simply incredible."
Juventus have been boosted by the addition of French striker Nicolas Anelka to their ranks, a player with invaluable European experience.
But Lennon insists that Celtic must be wary of whoever is selected to lead their opponents' attack, with Fabio Quagliarella and Sebastian Giovinco also available for the Italian champions.
He said: "I don't know how much football Anelka has played in the last few months, so whether he's been brought in for domestic football or this game, I don't know. We had them watched on Saturday, but we know that whatever two strikers they use will be quality."
Nigerian defender Efe Ambrose could yet be included in Celtic's plans for the tie, despite the player turning out for the Super Eagles in their African Nations Cup win against Burkina Faso on Sunday.