The Scot remembered his decision to drop goalkeeper Jim Leighton for the replay of the 1990 FA Cup final against Crystal Palace after a poor showing in the first clash.
"Players react differently," said the United boss in the Manchester Evening News. "Some accept it, others find it hard. It depends on the nature of the personalities. But it doesn't deflect me from picking what I feel is the correct team.
"In 1990, I made the right decision. I was disappointed for the lad at the time because Jim took it badly but that is why I speak to my players before I pick my team.
"You cannot think about how much a player costs when you are picking a team. Once that player is signed it is not as if you can go to the tax man and ask for a rebate if he doesn't play.
"Others might not agree with my choice and the recent FA Cup semi-final was a case in point.
"But I never allow anyone to cloud my judgement. I am very clear-minded about that."