But Ferguson was able to broker a move for the Madeira-born winger after telling Mendes that he wanted Ronaldo in Manchester immediately.
Mendes said: “I've always maintained that the coach is, in the end, the most important component in any transfer.
“Cristiano Ronaldo is a perfect example.
“Every club wanted him, but they all wanted him to have another season loaned back to Sporting.
“The only person who seemed willing to take him on immediately was Sir Alex Ferguson and, at that time, I had no doubt it was the best solution.
“My decision, made without a second thought, was that Manchester United was the ideal club for him. I'm sure that, if Cristiano Ronaldo had stayed at Sporting, he wouldn't have played half the games he played for Manchester in the first season, at the end of which, by the way, he was voted the team's best player by the fans."