McGuinness backed the Everton manager's arrival and admits he expects Sir Alex to still be a regular attendee at the youth matches next term.
"David Moyes has probably watched our youths a lot and the Reserves," he told manutd.com. "You see him at Under-21 games. One point about David that nobody really knows is I was the first one to try and get him here as a coach.
"I was on a full-badge coaching course with him and he stood out. He'd already done his coaching badges in Scotland but was still a player at Preston. He really stood out for me and the manager gave me the job as a director of the Centre of Excellence, where we needed coaches for the teams. I asked the manager and he said he knew his dad and knew David. He said why don't you ask him so I rang him up and he said: 'I would love to, I'm really flattered but, this week, I'm going to be made assistant-player manager of Preston'.
"So I said: 'Alright, thank you very much' and that was when I got Warren Joyce involved for the first time. I think he was at Burnley at that time as a player. He took the Under-16s with the likes of Wes Brown, Richie Wellens and Adam Griffin, these types of good players. So it was a good choice there as they have both been successful managers - Warren has obviously come back to us again after being a manager and David Moyes will be coming here. Obviously I'm a good judge of the managers!"