Ahead of Jose Mourinho and Cristiano Ronaldo's reunion at Old Trafford this week, we look at the history of their relationship in their own words.
The pair, who spent three years together at Real Madrid between 2010 and 2013, will be on opposite sides when Mourinho's Manchester United host Ronaldo's Juventus in Tuesday's Champions League group stage clash.
There has always been plenty of focus on how the manager and his former player get on - and while Mourinho praised Ronaldo as one of the sport's all-time greats in his pre-match press conference, there have been rocky moments too.
Here, Andrew Dickson looks back at a decade of ups and downs between the two from before, during and after their time with one another in the Spanish capital...
Long before their paths first crossed, Ronaldo and Mourinho had very different upbringings in their native Portugal.
While the man who would later manage the country's biggest two clubs, Benfica and Porto, came from a middle-class family, the same could not be said of his compatriot.
Indeed, the fact Ronaldo's childhood was an impoverished one on the island of Madeira was the subject of one of the first verbal jousts between the two in 2007.
With Ronaldo - then at United - helping his team win the Premier League by six points from Chelsea, he claimed Mourinho "does not know how to admit his own failures".
The Stamford Bridge coach responded first by calling the player a liar then gave a barbed view on comments Sir Alex Ferguson made in relation to the row.
He said: "It's a game where a kid had some statements not very… not showing maturity and respect, maybe difficult childhood, no education, maybe the consequence of that.
"Sir Alex felt he had to protect his boy. But normal things… I have no problems with him [Ferguson]. I have no problem with the boy."
Starting out at Real
Having won the Champions League at the Bernabeu only days earlier with Inter Milan, Mourinho moved to Real in May 2010.
Much of his first campaign in charge passed off without major conflict - but there were rumblings of unrest with Real's star man as the season drew to a conclusion.
Having beaten Barcelona 1-0 in the final of the Copa del Rey a week earlier - with Ronaldo heading the winner in Valencia - Real hosted their rivals in the Champions League semi-finals first leg.
Mourinho adopted a defensive approach but his plan failed, with a Lionel Messi double putting the visitors in command ahead of the return game.
Ronaldo was not pleased and asked if he liked the kind of football Real played, he said: "No, I don't but I have to adapt to what is asked of me. This is the way it is. We have a strategy."
He paid for speaking out and was dropped for the next league game, a 3-2 home defeat to Real Zaragoza, although he did start the other five remaining matches.
A need to co-operate
While the pair were starting to have differences of opinions, they needed each other in order to be successful and both appeared to recognise that.
Agent Jorge Mendes, who represents both men, acted to bring them on to the same wavelength and succeeded in getting both Mourinho and Ronaldo to offer each other their backing publicly at various points.
That undoubtedly made for a less bumpy ride but did not smooth the road entirely and mediation only went so far.
In fact, Mendes' presence as a common denominator almost appeared to burden Mourinho, who at times seemed to be feeling an obligation to make a relationship with Ronaldo work.
He once said: "I have to look after you because you're my brother's brother - and when someone is their brother's brother, that makes them a brother as well."
Breakdown in relations
Mourinho's second season at Real saw his team win the title by nine points from Barcelona, a feat made all the more spectacular by their final haul of 100 points.
As good as that was, the way things unravelled the following season was just as notable, with a 24-point swing seeing La Liga go to Barcelona instead.
Inevitably, relations between Real's two volatile Portuguese icons disintegrated and the closer they approached the season's end, the worse it got.
After scoring in their first league win of 2012/13 at the third attempt against Granada, Ronaldo did not celebrate.
When he was asked about his reaction afterwards, he described the squad's mood as "sad", something Mourinho would remember as he pointedly used the same word near the end of a disastrous campaign.
By then, he and Ronaldo had clashed after a 2-0 Copa del Rey win against Valencia in mid-January, when the manager had expressed his anger at the player not tracking back.
Spanish football expert Guillem Balague later claimed in his 2015 biography of Ronaldo they almost came to blows, with the Portugal international having to be held back.
Ronaldo is understood to have said: "After everything I've done for you, this is how you treat me? How dare you say that to me!"
With their relationship at breaking point, Ronaldo's response to a question about Mourinho's future at Real was telling: "It doesn't matter to me. What matters to me is my future and the club."
Ronaldo scored his 200th goal for Real in a 6-2 win over Malaga in May 2013. Mourinho's time would be up before the month was out and the player's reaction again told a story.
The manager had criticised him before the match and Ronaldo responded after his strike by shouting an obscenity at his coach.
Pointing to the ground, he also yelled: "I'm here, I'm here". The suggestion was he did his talking on the pitch rather than off it.
He didn't take it very well because maybe he thinks he knows everything and the coach cannot help him develop further.
The parting image of the pair summed up where they had got to. Before Mourinho's last match in charge, a photograph showed them both in the tunnel, steadfastly avoiding eye contact.
It was an unquestionably acrimonious split - and it looked certain they would never work together in football again.
Repairing the damage
At first, Mourinho used an appearance on Spanish television to express the issues he had with Ronaldo.
He said: "I had only one problem with him, very simple, very basic, which was when a coach criticises a player from a tactical viewpoint trying to improve what, in my view, could have been improved.
"At that moment, he didn't take it very well because maybe he thinks he knows everything and the coach cannot help him develop further."
Soon after, Mourinho's second spell at Chelsea was announced and he was asked about Ronaldo again. He dismissed the notion of a link between them - yet also seemed to be thawing.
He said: "The relationship does not exist. He plays for Real Madrid and I'm at Chelsea. You would not find us hanging around together.
"I remember the good and the not so good. I remember he is a goal machine, he helped me to become a champion, to win the cup and the Super Cup.
"He probably also helped him and each of us to make history in winning the league with 100 points against the best Barcelona side in history.
"Cristiano gives me great memories and I wish him all the best in his career, for his country and his club."
With time came a more favourable view - first: "Ronaldo's an incredible player. It's like Zinedine Zidane for the French, there will be no other. He is incredible, he's a goalscoring machine."
And then: "Coaching him was the highlight of my career. He's the most professional player I've ever met. A coach and a player may have their differences at a given time, but it ends there."
Did those words come with help from Mendes or simply because Mourinho no longer had the intensity dealing with Ronaldo brought him?
Whatever the reason, the perception was the rift was healing from both sides, with Ronaldo saying: "Work with Mourinho again? Why not?"
He later described Mourinho as the best manager he has ever worked with - more than father figure Ferguson - adding: "I would put him at the top, I always say that."
I would put [Mourinho] at the top, I always say that.
Tensions do still linger though. Mourinho criticised Ronaldo's actions after he came off injured in the Euro 2016 final but proceeded to prowl the touchline, barking orders for the rest of the game, alongside manager Fernando Santos.
Mourinho told Portuguese channel SporTV: "Cristiano Ronaldo didn't help in any way by doing that. There were 11 players on the pitch and the person in charge of directing them was the coach.
"What my experience tells me is that it is in these moments, when important decisions might need to be made, the players are lost in their own little worlds."
However, the feeling going into the pair's reunion at Old Trafford is that while their time together was not always plain sailing, both Mourinho and Ronaldo respect the other's achievements.
"He is one of the best players of all time - it's as simple as that," Mourinho said ahead of the game.