He arrived as a relatively unknown 18-year-old in 2003 before going on to establish himself as the one of the best players in the world.
Ronaldo scored 118 goals in 292 games for the Old Trafford club and has accepted that the influence of Rio Ferdinand, Ryan Giggs, Paul Scholes and Ruud van Nistelrooy helped shape his game and improve him.
Cristiano Ronaldo has shed light on four players he watched at Man United to improve
Ruud van Nistelrooy (left) was one player Ronaldo namechecked from his time at Man United
If you’ve got a little intelligence, you look and take example from those who are doing things better than you,’ the Portuguese star told France Football.
‘That’s what I did when I was in Manchester with Ryan Giggs, Paul Scholes, Ruud van Nistelrooy, Rio Ferdinand… if you don’t learn from guys like that, you’re an imbecile.
‘The goal isn’t to imitate but to take aspects from those who are the best and adapt it to your own personality. That’s what I did. I had some talent and I watched them.’
Ronaldo definitely took plenty from the veterans in the side and went on to be a hit in Manchester.
The five-time Ballon d’Or winner picked up three Premier League titles, a Champions League, an FA Cup and two League Cups with United.
Ryan Giggs (left) was a veteran in the side and he was crucial in helping Ronaldo develop