Manchester United boss Sir Alex Ferguson admits Cristiano Ronaldo must learn to handle the pressure of being Europe's No1 player.

The Ballon d'Or winner got involved in an angry half-time confrontation with Boro skipper Emmanuel Pogatetz before catching the Austrian with a nasty-looking tackle in the second half.

Thankfully for United, the Football Association decided not to take any action, leaving Ronaldo free to face Southampton in the FA Cup on Sunday.

Ferguson is wary of discussing Ronaldo's conduct too much as he feels the 23-year-old is under the microscope enough already.

However, he does see why certain situations occur and feels the aftermath is the price of being the world's top player.

"Of course I can understand Cristiano's frustration," said the Scot.

"Enough has been said about it already but I can understand it.

"He has produced little moments of displeasure at the treatment he is getting. They are trivial things but, as he has said himself, because it is Ronaldo it is magnified.

"That is the penalty for being a great player. He has to understand that."