The Portuguese forward instead joined Real Madrid in a world record £80million deal.
“Cristiano reached an agreement on December 8 2008 with Manchester United to come to Real Madrid,” Calderon told Spanish Eurosport.
“There was no negotiation about this, the signing was already done. I did my bit.”
He continued: “The player, in a gesture of good faith and clear desire to come to Madrid, agreed to a clause which could have inflicted a financial penalty of 30 million euros.
“But then Barcelona and Inter Milan tried to sign him too. It was a difficult situation because for United that would have solved the problem.
“It’s very well known that Alex Ferguson is not a friend of Real Madrid, does not see Madrid in good light because they are sporting rivals, in trophies and European competition.
“If he had gone to Barcelona it would have been very good because it would have allowed them to resolve that problem and would have taken away a great player from Real Madrid.
“But you have to say that the player remained firm and decisive in not going to another club that wasn’t Real Madrid.”
Calderon added: “He rejected them and that is certain.”
