The Portuguese international spent six seasons with Ferguson at Old Trafford before moving to the Santiago Bernabeu but still remains fond of his old manager three years later.
"He's a fantastic person. A human person. He taught me many things. Like I said before, he's like a father in football. I really miss him and my relationship with him," the Sun quoted Ronaldo, as saying.
"He is very tough. I think he cannot be like that because, how old is he? 70? It's not good for his heart," he added.
"He's still tough, strong, I remember him the first time I saw him he was with the same power," he said. (ANI )