Ronaldo returns to United on Tuesday night for the first time since he left for Real in 2009 after six hugely successful years with the Premier League club.
He was on target in the first leg of the UEFA Champions League last-16 tie when his header in the Santiago Bernabeu earned Real a 1-1 draw.
The return meeting is an eagerly anticipated encounter and Ronaldo is hoping he can again score against his former club.
"It would be a beautiful sensation," said Ronaldo. "If I score against them, it would be spectacular.
"I can't say how I'd celebrate - it would be something spontaneous - but I'd love to be in that situation."
The Portugal international looks back fondly on his time with Sir Alex Ferguson's side and he is expecting a positive reaction from United supporters.
He added: "I'm sure they will receive me well.
"After the years I spent there and the friendships I have, I'm sure it's one of the places where they'll applaud me most. It was a beautiful time."
United full-back Patrice Evra also expects Ronaldo to be warmly welcomed at Old Trafford, saying: "Cristiano will get a great reception on Tuesday because of what he achieved for Manchester United.
"The fans will never forget what he did. Also, he still loves the club.
"I remember after the game in Madrid we had a chat. He said it was going to be more difficult to come here.
"This is his house, so there will be a lot of emotion. It is difficult when you play with love and I hope he doesn't play well because of that.
"But Ronaldo is a winner. He is a big competitor. If he can win against Manchester United he will do it."
And United boss Sir Alex Ferguson commented: "Cristiano will get a good reception. All our former players, especially the ones who have been great for this club, get a good reception when they return."