Cristiano Ronaldo says leaving Sporting Lisbon for Manchester United was the making of him as an 18 year-old.

"Leaving my family and moving to England was the worst moment of my career," he said. "It was a very difficult part of my life because I'd always had a lot of support from my family.

"To go to a different country, to play a new style of football, was awkward. I cried every week, but I also grew a lot as a person and player. It was a very important time for me."

Ronaldo has blossomed into the world's best player at United and says he feels privileged to be called one of the club's all-time greats.

"It's an honour because the club has had so many great players," he said. "To be part of this club's history makes me very happy."