When Real Madrid were flying under Jose Mourinho two seasons ago, and Cristiano Ronaldo was laying waste to La Liga’s defences, the two Portuguese men seemed thick as thieves.
But as Mourinho’s grip on Los Blancos began to fray, and the team relinquished their hard-fought league title and floundered in Europe yet again, the received wisdom of Mou and CR7’s buddy-buddy relationship proved something different.
They may not have gone their separate ways like Mou did with Iker Casillas, Sergio Ramos and eventually even Pepe. But it was clear their shared nationality was no longer an immutable bond.
And now that The Special One has taken up his old office at Chelsea, he has acknowledged that there was one major sticking point between him and Ronaldo.
While he accepts that CR7 was great to work due to his ability to star within the system, Mourinho says that the player’s inability to accept constructive criticism or tactical advice was a hindrance.
In effect, Mourinho has accused superstar Ronaldo of being a know-it-all.
"Cristiano has had three fantastic seasons with me, I don't know if they were the best of his career because he had some fantastic moments with Manchester United,” Mou told Punto Pelota.
"I think we created a fantastic situation for him tactically in which he could express all his potential and turn that into records and goals.
"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," Mou explained of his sometimes strained relationship with Ronaldo.
"And at that moment he didn't take it very well because maybe he thinks he knows everything and the coach cannot help him to develop more.”
Perhaps Ronaldo has a point, however. After all, he is renowned as a player who simply worked harder than anyone else to refine his natural talents to the point of almost superhuman ability.
And it is far easier to argue that Real Madrid need Ronaldo much more than they needed Mourinho.
And that is why, even if CR7 is a know-it-all who thinks he is beyond coaching, Madrid are doing everything in their power to keep him, while they couldn’t get Mourinho out the door fast enough.
"Cristiano Ronaldo is priceless," Real president Florentino Perez reiterated according to El Mundo.
"We will do it (win the club’s 10th European Cup ). And Cristiano will score a goal in the final."