Cristiano Ronaldo spent so long on the training ground that Sir Alex Ferguson ordered him to leave because it was too close to a game.
The legendary boss feared the young Ronaldo would wear himself out perpetually practising all his trick, flicks and skills.
Nicky Butt came off when Ronaldo made his first Manchester United debut in 2003 and in the new book “Viva Ronaldo”, Butt reveals the secrets of Ronaldo’s determination to make it to the top.
Butt said: “Ronaldo was to emerge as a genius but it wasn’t just about his talents that took him right to the top.
“It is often said that certain players worked hard, stayed behind for some extra training or to practise their techniques, but with Cristiano it was total dedication, total commitment, and total hard work.
“He didn’t have a God given physique, it wasn’t given, he worked hard to achieve it. He actually came to us as a skinny, scrawny young kid, and worked hard to get that physique over many, may years.
“He had to reach a new level of physical strength because the Premier League demanded it, and he had plenty of opportunity to see at first hand how physical and tough it can be when he was up against, even in training, the likes of Roy Keane and Jaap Stam.
“We would also see him work relentlessly on his free kicks and he would tell us about something he had seen somewhere, and he wanted to perfect it, and he would work again relentlessly until he did.
“It all went beyond dedication, he was obsessed with football.”