Sir Alex Ferguson ended up falling out with some of his star players during his remarkable 26-year spell as Manchester United manager.
David Beckham, Ruud van Nistelrooy and Roy Keane were just three of the stars who ended up leaving Old Trafford after falling out with the fiery Scot.
However, one player who managed to leave United on good terms - in fact, excellent terms - with Ferguson was, of course, Cristiano Ronaldo.
Ronaldo agreed to stay at Old Trafford for one more season in the summer of 2008 after Ferguson promised him he could complete his dream move to Real Madrid if he gave United 12 more months of service.
The Portuguese superstar agreed, moved to the Bernabeu a year later, and his relationship with Ferguson has been rock-solid ever since.
Not many players and managers have a father-son type relationship - but it’s fair to say that Ronaldo and Fergie do.
Here are 11 times they’ve shown over the years that they’re just like father and son…
When Ferguson allowed Ronaldo to be with his dying dad
Back in 2005, Ronaldo’s father Jose Dinis Aveiro was critically ill in hospital. Ferguson didn’t hesitate to allow Cristiano the opportunity to be with his dad - even though it meant missing key games - and this gesture meant everything.
"When my daddy was sick in London, and he was in hospital very bad [asks interpreter] in a coma,” Ronaldo explained on the BBC documentary ’Sir Alex Ferguson: Secrets of Success’ in 2015. "I had a conversation with him [Ferguson] and I said: ‘Boss, I don't feel good.’
"We are in a key moment in the Champions League, and I said I don't feel good and I wanna see my dad. He said: ‘Cristiano - you wanna go one day, two days, one week? You can go. I'm going to miss you here because you are important, but your daddy is the [priority].’
“When he told me that, I feel like this guy is unbelievable. He the father of football for me."
Fulfilling his Real Madrid promise to Ronaldo
Back in December 2008, when it first became apparent that Madrid were seriously interested in signing the world-class winger, Ferguson said: "You don't think we'd get into a contract with that mob, do you? Jesus Christ. I wouldn't sell them a virus. So that's a no — there is no agreement between the clubs."
But despite his angry reaction, Ferguson had an agreement with Cristiano - and he didn’t break it.
Ronaldo was unveiled as a Real Madrid player just six months later.
Ronaldo sent special message for Ferguson’s statue unveiling
Ferguson’s statue outside Old Trafford was unveiled in November 2012 - just six months before he stunned the club by announcing his retirement.
During the unveiling, which was attended by hundreds of United fans from the local area, Fergie received a special video message from Ronaldo, who apologised for not being present due to his hectic schedule.
Ronaldo’s tribute at the Sports Personality of the Year awards
In December 2013, Ferguson received a special BBC Sports Personality Diamond Award during the show's 60th edition.
And during the tribute, he received another special recorded video message from Ronaldo.
“You were like a football father to me,” Cristiano said. “You deserve this award because you are a fantastic manager, a fantastic person and the number one.”
Fergie attended Ronaldo’s film premiere
Ferguson was never going to miss the premiere of Ronaldo’s film - titled ‘Ronaldo’ - in November 2015.
This was a big moment for the Portuguese icon and having his former boss by his side on the red carpet must have meant a lot.
Touching moment after Euro 2016
After Portugal won the Euro 2016 final, Ferguson - waiting in the crowd as the players walked down the steps - hugged Nani and then Ronaldo.
What a beautiful moment.
After the 2017 Champions League final
Ferguson was the special guest at the 2017 Champions League final in Cardiff and it was fitting that Ronaldo, who scored two goals in Real Madrid’s 4-1 win over Juventus, produced a Man of the Match performance.
Fergie handed Ronaldo his Man of the Match award after the game…
And the two men also shared a special moment, along with Ronaldo’s son, in the tunnel…
When Ferguson argued that Ronaldo is better than Messi
When it comes to the age-old Ronaldo v Messi debate, there’s only one winner in Ferguson’s eyes.
"Ronaldo is tough," the former United boss told BBC Sport in 2015. "People say 'who is the best player in the world' and plenty of people quite rightly say Messi. You can't dispute that opinion.
"But the thing about Ronaldo... Ronaldo could play for Millwall, QPR, Doncaster Rovers or anyone and he'd score a hat-trick. I'm not sure Messi could do it.
"Ronaldo's got two feet, he's quick, he's good in the air and he's brave, though Messi's brave too of course. I just think Messi is a Barcelona player."
Ronaldo sends Ferguson message of support after brain surgery
Ferguson came close to losing his life in 2018 after suffering a brain haemorrhage - and Ronaldo, along with everybody else, was desperate to see the legendary manager pull through.
He posted the following message on Instagram:
He then met Fergie after Juventus played Man Utd months later
Fortunately, Ferguson made a remarkable recovery and met up with Ronaldo after Juventus played Man Utd in the Champions League the following October.
“A great coach and above all a wonderful man,” Ronaldo tweeted, alongside a photo of them both, “Taught me so many things inside and outside the pitch. Great to see you in good shape, Boss!”
Ferguson’s special message to Ronaldo after winning Portuguese award
Ronaldo won the Portuguese Player of the Year award for a record 10th time last September and received a special video message from his footballing father.
"Congratulations on a great achievement and a wonderful night you're going to have in Portugal,” Ferguson said in the video.
"I'm really sorry I can't be with you, but I look back and see you as a young lad at 17 years of age who came to Manchester United, how you have progressed as a human being and a fantastic sportsman.
"I want to say to you, and your mother, and all your family, and all of your kids; well done.
You have been an absolute pleasure for me to have known, to have worked with, and to have seen you progress into the footballer you were.
"So, good luck, have a great night, and well done."
There’s no relationship in football quite like Ronaldo and Ferguson’s.
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