Rio Ferdinand applauds Cristiano Ronaldo's transformation

Former Manchester United centre-back-turned-pundit Rio Ferdinand believes Cristiano Ronaldo has undergone a massive transition since his days as a teenager at Old Trafford.

Ferdinand, who played alongside Ronaldo for six seasons following the Portuguese international's high-profile move from Sporting Lisbon, reckons the man who scored his 500th career goal Wednesday has changed in the years since he first arrived at the legendary English side.

"When he came to Manchester United he was a show pony, he wanted to do skills, he wanted to show how good he was," Ferdinand told BT Sport.

"Then, he realised it was about end product."

Eighty-four goals in 196 appearances for United is an absurd standard for someone who had yet to evolve into the complete player he is today.

"To become the best player in the world it was purely about scoring goals or setting up others, and having an impact on games," Ferdinand continued. "He’s forced himself to become that guy. He’s been relentless, season upon season raising that bar. That’s greatness right there."

Since an £80 million move from United to Real Madrid in 2009, Ronaldo has scored 324 times in 308 appearances, refining his skill set to become one of the world's two best footballers, along with Lionel Messi.