Sir Alex Ferguson has not written off the prospect of Cristiano Ronaldo returning to Manchester United one day.

Ronaldo began a new phase in his career on Monday night when he made his debut for Real Madrid in a scrappy 1-0 win over Shamrock Rovers.Real paid a world record £80million to let Ronaldo fulfil his childhood dream and turn out for the Madrid giants.

And while Ferguson does feel the 24-year-old Portuguese superstar will prosper at the Bernabeu, he cannot entirely discount the possibility of Ronaldo eventually coming back to Old Trafford, where he spent six years developing into the world's best player.

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"He may come back, you never know," said Ferguson. "Sometimes it happens that way.

"He loved United. If you look back at the six years he had with us, he never missed training. That's one of the things he has above all other players - he was never injured, he always played. And his best is yet to come. He is only 24."

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