United were leading 2-1 on aggregate against Spanish giants Real thanks to a Sergio Ramos own goal, when Turkish official Cakir showed the Portuguese winger a red card for a high challenge on Alvaro Arbeloa.
"A yellow card maybe, but a red card? Absolutely not.
"I don't think it matters whether it's a referee in the Premier League, La Liga or a Champions League game.
"It was just a bad decision. Referees are human and make mistakes - there is no problem with that - and sometimes it goes against you.
"But we are allowed to say when a referee gives a poor performance, and that was a very poor decision."