Sir Alex Ferguson has warned Cristiano Ronaldo not to let his frustration get the better of him and warned him: "You can't get everything your own way."
Ronaldo was the key figure in United's march to the Premier League and Champions League double last season but boss Ferguson has made sure the Portuguese star knows what is expected.
He said: "No, I don't accept that he will give goals away because of the player he is, I speak to him about it. I don't accept that from anyone.
"In European football, if you give the ball away it takes a long time to get it back.
"He always feels he's not getting the proper protection from referees and I think that, maybe, in quite a few cases he is right, and a few cases he is not right.
"It's hard when a player who wants to entertain doesn't get everything his own way. But you can't get everything your own way.
"He understands that and there's not a problem with that. It's just a frustration that he feels he doesn't get the decision and he gets upset about it.
"I think, obviously, he doesn't enjoy that and he knows he's letting himself down more than anything.
"He holds his hands up. I have had to remind him about that but I'm not getting into what has been said."