Jose Mourinho believes Cristiano Ronaldo has a "natural advantage" which makes him one of the greatest players in football history.
Mourinho, managed Ronaldo during his spell at Real Madrid from 2010 to 2013, where he had first-hand experience of the Juventus star.
Ronaldo's athleticism is viewed as a key difference between him and his rivals, but Mourinho believes the mental characteristics of him are "in his DNA".
"The difference is all in his head, it is a natural advantage, it is in his DNA," Mourinho told Eleven Sports .
"Ambition, motivation, personal pride are all things that are not bought and that are there from birth.
"Ronaldo will be like that until the end. He is one of those mentally special players."
Mourinho's praises of Ronaldo's brilliance came after the Portuguese were linked with a possible reunion at Juventus.
The Italian champions are eyeing a new manager after the departure of Max Allegri, and reports had suggested Ronaldo was pushing for Mourinho to get the job.
And Mourinho recently fuelled the speculation by hinting he had talked to Ronaldo regarding the job.
Mourinho told BeIN Sports: "One of the players that I have a great relation with, he plays for a team and he told me, 'You should come here next season', and I told him, 'They don't love me'".
"He told me, 'You win three matches and they will start loving you'".