Footage Shows Roy Keane Berating An 18-Year-Old Cristiano Ronaldo For Failing To Track Back In Training

"He wasn't just keeping an eye on whose standards were dropping, though, he was setting them himself. He could talk the talk and walk the walk; he was just relentless every day.

"I wish people could see how much this guy trained; he was unbelievable."

A training ground clip from 2003, when Ronaldo was just 18-years-old, has been doing the rounds on social media of late.

As you can see in the footage below, the Portuguese winger failed to track back in the session and as a result, the opposition went on to score past goalkeeper Tim Howard. "Cristiano, come on!" cries Keane.

As mentioned earlier, when Keane turned up to training early, the rest soon followed.

Former Manchester United defender Quinton Fortune expanded on the unspoken rule. "You just picked it up from day one," he said. "You needed to be on your toes every day in training, because if you weren't someone else would take your place. It was as simple as that.

"If training started at 10:15am, you'd be thinking 'OK, I need to be in at 9, maybe even 8am'. You'd get in early, have your breakfast, do your stretches, be out on the pitch at 10am, ready for training.

"We would treat every training session like it was our last, and that became a habit for everyone at the club. You came in and just thought 'is this normal?' but match day would come around and it would be easy."