The Real Madrid star is facing the Red Devils for the first time since his move to the ‘Casa Blanca’ and his former Manchester boss thinks he is more talented than the French legend Zinedine Zidane.

The Portuguese still holds the record of the world’s most expensive transfer when he made his £80 million move from Old Trafford to the Bernabeu in 2009 after winning the Ballon d’Or with Man U.

Ferguson says that his skilss surpass even those of the legendary ‘Zizou.’

“Florentino Perez had all the Galacticos at Real Madrid when he was president first time around,” Sir Alex told reporters. “He had [Luis] Figo, Zidane, Roberto Carlos, Raul in that spell. But I don’t think any of those players were as good as Ronaldo.

“Zidane was a fantastic player, Figo was a fantastic player. But not as good as Ronaldo. So I think Mourinho’s team are still living up to the reputation that Real Madrid can produce the top players.

“Ronaldo has beaten all the records there. He’s beaten [Alfred] Di Stefano, [Ferenc] Puskas, Hugo Sanchez. So obviously he is indelibly printed in their history now.

“You have to say he is pivotal to all they do – 179 goals in 178 matches tells its own story. I think I might have to think about blackmail. I might have to tell a true story about him!

“He’s a fantastic player. I knew he would improve tremendously, he was still young when he left us.”

“I told them upstairs [the Glazers]. We should have asked for £150m; we probably would have got it.”

“You are talking hundreds of millions; I don’t see it,” he added.