Cristiano Ronaldo at Manchester United was a joy to behold.The Portuguese winger developed into a ferocious player with predatory instincts at Real Madrid, but at Old Trafford he was much more of an entertainer.Trickery, speed, explosiveness - Ronaldo had it all, regularly leaving fans speechless with his array of skills.It was clear from his debut against Bolton Wanderers on August 16, 2003, that Man United had a future superstar.Ronaldo was introduced as a second-half substitute and instantly set about putting on a show, ghosting past defenders and winning his side a penalty.It was a sign of things to come and by the 2007/08 season, Ronaldo was a world-class talent.And boy did he know it.Ronaldo messes with Chelsea fansRonaldo enjoyed playing with the fans just as much as he did opposing defenders.We’ll never forget the time he showed off his skills to Chelsea supporters at Stamford Bridge ahead of a match.Ronaldo messed up a skill, which prompted jeers from the home crowd.How did he respond? By flicking the ball up and over his head and catching it between his knees.

Pure box office.

Ronaldo left Man United in 2009 after scoring 118 goals in all competitions for the Red Devils.

Many players came and go during Ferguson’s reign but the Scot considers Ronaldo to be the greatest of them all.

“Cristiano was the most gifted player I managed,” Ferguson wrote in his autobiography, per the Independent.

He surpassed all the other great ones I coached at United - and I had many.

Ferguson coached the likes of Wayne Rooney, Paul Scholes and Ryan Giggs. Yet he considers Ronaldo to be the best of all of them.

And the winger was only just getting started.

He took his game to another level at Real Madrid, where he cemented himself as one of the finest players in the history of the game.