Cristiano Ronaldo was just a mere mortal 18-year-old when he arrived at Manchester United.
Of course, the rest, as they say, is history.
Sir Alex Ferguson played no small part in CR7's journey to become arguably the greatest player in the world, hence why the Portuguese famously refers to him as his 'football father'.
Now that he's scored an incredible 265 goals for Real Madrid, following up 84 from his time at Old Trafford, it's easy to forget he wasn't always the finished article.
In fact, Fergie actually noticed some bad habits about him in training, and he had a pretty interesting way of ironing them out of his game.
Ronaldo's former colleague, Darren Fletcher, has recalled how the United boss instructed the attacker's team-mates to give him a good kicking - as he knew it would toughen him up.
CR7's bad habit
"Ronaldo had a real tough time for the first two or three years when the manager tried to toughen him up," Fletcher told a FourFourTwo documentary, as per the Manchester Evening News.
"He kept on to the ball too long and he wasn't delivering it into the box he was beating men two or three times and his end product wasn't there.
"When he kept onto the ball he learned the hard way there's no doubt about that. He got kicked but that was the way of telling him if you do this your not helping the team and your going to get kicked in games.
"It was a tough school at Manchester United at the time we all experienced it I experienced it and I thought that was part of what made him the best player in the world."
Ronaldo must have got used to being kicked now - as let's face it, it's often the only way defenders can stop him.
Here's the full documentary, made to mark 30 years since Ferguson took the reins at the Theatre of Dreams.
Did Ferguson make Ronaldo into the world's best player? Have your say in the comments.