Ferguson has hinted he is monitoring Ronaldo's situation in Madrid.
"Cristiano gave his heart to Manchester United," reflected Ferguson. "When he was involved in the incident that saw Rooney sent off at the 2006 World Cup, I liked his attitude. Here in England, though, we raged against him and he wanted to leave.
"I gave him a promise: give me one more season and you can go to Real. He put in an exceptional season. He never sulked. He was on fire. He is a nice guy. I do not know if he is as happy at Real. But I must admit that his goal ratio is better in Spain than in England.
"He will receive a special ovation on Tuesday, but once the game starts that will be over. They will boo the same guy they applauded."