Sir Alex Ferguson’s legacy at Manchester United stands out even more in the wake of his retirement.

It was five years ago that Ferguson stepped away from the club, and they’ve never had it so well since.

David Moyes and Louis van Gaal both tried to continue the dominance that Ferguson started, but neither managed to do so.

Now it’s the turn of Jose Mourinho, who hasn’t done much to suggest that the glory days will return to Old Trafford soon.

Ferguson earned the respect of his players at Man United, making sure they all knew just what it meant to play for the famous club.

That meant not allowing players to swap shirts at the end of domestic matches.

Ruud van Nistelrooy did so after the a 3-1 defeat against rivals Manchester City in 2002 - and he quickly earned the wrath of Ferguson.

Ferguson was fuming

Gary Neville has revealed what the Scot said in the dressing room after Van Nistelrooy walked in holding a Man City top, with his own United shirt nowhere in sight.

“The City player had come up to him and swapped shirts,” Neville said on the Quickly Kevin, Will He Score? podcast.

"He said, 'You do not give away one of those shirts. They're my shirts. They're this club's shirts, they're not your shirts. You're just wearing them temporarily. That's not your possession to give away.’

"He stopped us swapping shirts in domestic games.

"I think he said after that game, 'I should let the fans in here. I should let the fans come in here and speak to you.'"

One imagines Van Nistelrooy got the message.

It was a perfect way of reminding the players that nobody is bigger than the club, and that to play for Man United is an honour.

The Red Devils would go on to win the Premier League title in 2002-03, but that defeat in the Manchester derby must have hurt.

Ferguson said after the match: "Quite simply, they have underachieved - they have received a rollicking and rightly so."