Manchester United assistant manager Mike Phelan has claimed that the club had to teach Cristiano Ronaldo to become more of a team player at the start of his career.
The Portugal international spent six years at Old Trafford after arriving from Sporting Lisbon at the age of 18 in 2003.
Ronaldo has gone on to become one of the world's greatest ever footballers, enjoying success with United, Real Madrid and Juventus.
Phelan feels that the key to the five time Ballon d'Or winner's success was making him "do things he did not want to" in training in order to transform his game.
"We had to try and get Cristiano to be a team player and he got it. In the end he got it," he told The Coaching Manual YouTube channel.
"There were certain things we did in training that made him do things he didn't want to do.
"Especially when the success came and after he moved to Real Madrid, there were certain things - when observing games at Madrid - that he definitely picked up at Manchester United. He was translating that further up the ladder of excellence. That's important and there's a satisfaction there.
"I don't claim to have created Cristiano Ronaldo. A lot of people have influenced him. But the biggest influence has been himself, his drive has been fantastic."
Phelan worked as a coach at United during Ronaldo's time at the club and returned in December 2018 as part of Ole Gunnar Solskjaer's backroom staff.