McGuiness struggled to handle replacing Sir Matt Busby back in 1969.
"Following someone as great as Matt Busby I know how David Moyes will feel," McGuiness told United Uncovered. "But David is a very experienced manager. It was my first managerial role when I followed Matt. I had coaching experience but it is different being a manager.
"David Moyes is an experienced guy and what he needs is the fans to get behind him. Let them cheer like mad. The fans will definitely get behind the manager and the players will be there as well. Knowing what he has done [at Everton] and knowing the man slightly, it's enough to say: 'He's the right sort'. He'll need good luck. Sir Alex will tell you he had good luck with the last-minute goals. David will get that winning feeling, I'm sure.
"The biggest thing in football, in life if you like, is self-belief, inwardly knowing you're going to do it. That's how people like Sir Alex and Sir Matt got on - that inward belief that they're going to make it - and I feel sure David Moyes will."