Alex Ferguson told Real Madrid on Friday that Manchester United would not be bullied into selling Cristiano Ronaldo.
Ronaldo scored in United's Champions League final win over Chelsea in Moscow on Wednesday but his contribution has been overshadowed by speculation from Spain that the winger might be moving to the Bernabeu in the off-season.
"Real Madrid are not the only club interested in Ronaldo, but other clubs are not saying so," Ferguson said.
"Do you not think we've not had interest from big clubs around Europe about our best players? Of course, we have," he told reporters.
"But they don't get into the nonsense (Real Madrid) get into.
"(Real) think they can ride rough-shod over everyone, but they won't do it with us. We only sold them Ruud van Nistelrooy and David Beckham because we wanted to."
United transferred former England captain Beckham to Real in 2003 and Dutch striker van Nistelrooy followed him in 2006.
Ronaldo prompted speculation on his future by sending mixed messages after the Champions League final victory.
"I don't promise nothing. I don't promise nothing to my mum, I don't promise nothing to supporters," he told Radio 5 Live.
"I want to stay but the future - no-one knows. I want to stay. We are going to see in the next two weeks, I don't say I make a decision."