Ronaldo to Manchester United refuses to go away with the Real Madrid star facing an uncertain future in La Liga.
The veteran, who has struck four goals for Portugal in his first two World Cup outings, suggested his time was up after their Champions League final win over Liverpool last month.
Since then, his mother has openly admitted she would Cristiano Ronaldo to join United, while reports have claimed he has his heart set on a return.
Doubts about a transfer have, however, arisen due to his turbulent relationship with Mourinho.
The duo fell out while at Real Madrid, despite helping Los Blancos win La Liga in 2012.
But Spanish website Diario Gol claim that will no longer be an issue.
And that is because Mourinho wants Ronaldo back at United to add an extra edge to their attack.
The Red Devils already have a plethora of attacking players at their disposal but Mourinho reportedly feels he is missing something vital up front.
However, if Anthony Martial carries through on his desire to leave the club, then United may have to splash the cash on a replacement.
Mourinho, Diario Gol report, thinks Ronaldo is exactly what his team needs and won’t be able to challenge for titles unless they sign a player of his calibre.
Meanwhile, speaking at the start of the month, former Real chief Ramon Calderon blamed Ronaldo’s Manchester United flirting for Zinedine Zidane’s sudden departure.
Zidane quit the club, citing exhaustion as the reason why.
But Calderon said: “First of all with the keeper – the President wanted to sign the Athletic Bilbao keeper and he said my keeper is Keylor Navas.
“Then there was talk of Lewandowski but we know he likes Benzema.
“And now the problems with Ronaldo and Bale – it’s a pity really, because I like Cristiano and it took me a lot of hard work to bring him to Real Madrid – but it wasn’t the right moment to say what he said and the way he said it.
“He knew he was going to have problems with Bale and Ronaldo.”