I heard Ruud van Nistelrooy talk about pressure and potential at Man United - Ruben Amorim should listen

It didn't take Ruud van Nistelrooy long to grasp that in joining Manchester United, he had arrived at a club that garnered worldwide support - and worldwide attention. The Dutchman argues only Real Madrid come close to United when it comes to the demands and the scrutiny and he should know, spending five years as a player at Old Trafford and then four more at the Bernabeu.

A decade in the doldrums has done nothing to lower the spotlight on events at United. If anything, the glare has become harsher since Sir Alex Ferguson retired in 2013, and a trophy-winning machine began to cough and splutter. Eleven years on, nobody has yet been able to offer anything other than a sticking plaster.

Ruben Amorim will be the next to try. The confident, charismatic 39-year-old is a new profile for United. He will take over from Van Nistelrooy tomorrow, becoming the club's sixth permanent manager since Ferguson and the 24th in their history. Only three have ever won the league title.

ALSO READ: Amorim has already shown he can fix United problem identified by Van Nistelrooy

ALSO READ: 'I believe' - Ruud van Nistelrooy set for United meeting with Ruben Amorim

United are a long way from such lofty aspirations right now, but Old Trafford will attract the biggest crowd of the Premier League weekend. Whatever is going on, this is a club that will dominate column inches, social media discourse, and radio phone-ins. When Amorim drives into Carrington for the first time on Monday, it won't take him long to grasp just how big this thing is.

For Van Nistelrooy, that lightbulb moment came a few weeks after joining for £19million from PSV Eindhoven in 2001, arriving at a club that had just won a third Premier League title in a row.

"When we landed in Bangkok on a pre-season tour in 2001 and I saw 100,000 people at the airport, that’s when I thought ‘ooh!’," Van Nistelrooy said ahead of his final game as caretaker manager this weekend. "That’s what I thought - then you realise what it is on a worldwide scale, and in Real Madrid it’s similar, wherever you go, the attention.

"In the end you learn to bring it down to focusing on your job and performing as a player or coach and dealing with those circumstances. That’s a big responsibility - we are all aware of it, but it’s also a challenge."

Van Nistelrooy plundered 150 goals in 219 games for United but still left under something of a cloud in 2006. There was a training ground bust-up with Cristiano Ronaldo and a gradual weakening of his relationship with Ferguson.

But time has been a healer, and the 48-year-old jumped at the chance to return to the club as a key part of Erik ten Hag's new-look backroom staff this summer. Van Nistelrooy arrived as an assistant manager, but with Ten Hag's grasp on the top job still weak, there was always a chance this promotion would arrive.

His four games in the hot seat have all been at Old Trafford, and against Leicester City today, he will seek to add a third win to the draw against Chelsea. The fact that the matches have all taken place at home has allowed Van Nistelrooy to rekindle his love affair with United supporters, and his final programme notes today are an impassioned thank you to them and an assessment of the future under Amorim.

He believes the future is bright, having worked with this group of players as a coach and now as their manager. There has long been a feeling that this club has lost its sense of self, that the aura that came with all that success under Ferguson has vanished alongside its more homespun values.

Van Nistelrooy is well placed to compare across the eras and while he can't explain what has gone wrong, he insists the place feels the same to him.

"Leaving in 2006 is 18 years ago, it’s quite a time I wasn’t part of the club, so it’s such a big question to answer to see what happened in those 18 years. For me the challenge was to come back and the motivation to be part of this, I feel the potential of this club will always be there," he said.

"The people who are here and are working, that’s what I experienced when I joined the club, that feels similar. It feels like the same club, that togetherness, that willingness to do better and to do well, that’s what the motivation is for all the people that work here and for the players. The target is clear, from where we are now, to improve. That will take time and it will take hard work, but that is the challenge for me, not necessarily to analyse what happened in the past but to make things better and that’s what I try to do every day."

That's why Van Nistelrooy wants to stay on under Amorim. The pair are set to meet on Monday to discuss a handover and what comes next. Amorim has enjoyed a hugely successful spell at Sporting, but this is another level entirely. So, has he taken on the biggest job in world football?

"When you go to manage or play for the biggest clubs that’s part of it," said Van Nistelrooy. "I have to say in my years in Real Madrid I experienced microscopic views and intensity as well, 20 pages in the papers every day, radio stations, social media…

"In the world really, United is there. But that’s also the challenge - to play and manage this club is a huge responsibility and I see that as a challenge whoever manages here."

United have tried the big names with big experience, in Louis van Gaal and Jose Mourinho. They tried another Scot (David Moyes), the former player (Ole Gunnar Solskjaer), and someone with Champions League success (Erik ten Hag). In Amorim, they have the youngest of those to try, as well as perhaps the most highly-rated, but that remains potential at this level. For Van Nistelrooy, experience is irrelevant.

"It's about the talent of a person that for me is the most important thing, big name, small name, call it anything you want in the end it's the person, and the talent and the qualities of that person who will make sure how things will go, so that's why it's not so important the name in this sense," he said.