What Sir Alex Ferguson, Roy Keane and rivals said about Cristiano Ronaldo following his first debut in 2003

MANCHESTER UNITED icon Cristiano Ronaldo is widely regarded as one of the greatest footballers ever to play the game.

But when the Portuguese ace first arrived at Old Trafford in 2003 as David Beckham's replacement, he was a tricky, talented but unproven winger.

Arriving at Man Utd as an 18-year-old, Ronaldo needed time to impress his illustrious colleagues and fill Beckham's daunting No7 shirt.

In fact, it took the now 36-year-old four years to register ten league goals in a single season - a feat he has comfortably achieved every year since.

But did the Premier League's best see his potential on debut? Here, SunSport recall what several famous names said about the teenage CR7.

Sir Alex Ferguson

Man Utd boss Fergie knew the club had something special when Ronaldo put in a stunning performance on Prem debut against Bolton.

Ferguson told the press: "It was a marvellous debut, I thought the pace was too slow in the first half and I knew Cristiano would add penetration.

"We have to be careful with the boy. You must remember he is only 18. We are going to have to gauge when we use him."

FREE BETS: GET OVER £2,000 IN NEW CUSTOMER DEALS

Sam Allardyce

Bolton's manager when Ronaldo made his Old Trafford bow was future England coach Allardyce.

Allardyce admitted: "He was different class, he looks a very exciting player and his introduction was crucial.

"He reminds me of Ryan Giggs when he first started. He can go inside, outside, uses both feet and runs at people.

"Everyone holds their breath when he gets the ball."

There have been a few players described as 'the new George Best' over the years, but this is the first time it’s been a compliment to me.

George Best on Cristiano Ronaldo

Roy Keane

Not everyone was that impressed with CR7's debut, though, including his skipper Keane.

The Irishman said: "It was 20 minutes, that's all it was. I think he won a penalty, but so what?"

But Keane quickly warmed to Ronaldo, later admitting: "How many times can I say it? The man's a genius. I'm sick of saying it."

Ruud van Nistelrooy

And Dutch icon Van Nistelrooy struggled playing with Ronaldo at first as he found it difficult to get on the end of his crosses.

The striker, a traditional No9, was bamboozled by the youngster's tricks and had no idea when the ball would go into the box.

Ex-goalkeeper Edwin van der Sar remembered: "I think Ruud was used to David [Beckham] crossing the ball every time he had it.

"David didn’t have pace to dribble and beat opponents, so he had to do something else. Ronnie had the pace and the tricks."

Van Nistelrooy and Ronaldo used to fall out over the latter's stepovers, with defender Rio Ferdinand admitting: "They had a couple of arguments.

"Ruud Van Nistelrooy kicked him one time and after that I kicked Ruud just to protect Ronnie a little bit and Ruud swung a punch at me and he missed."

Gary Neville

Neville knew how good Ronaldo was from an early age, suggesting he was Portugal's star player ahead of their Euro 2004 clash against England.

And that is some compliment, considering the great Luis Figo was still running the show for Portugal and Real Madrid.

Neville said: "He's not a show pony, he's the real thing... He's a special talent. I won't get a second's rest."

Alan Hansen

One of Ronaldo's greatest Man Utd performances came during his first season, when he scored in the team's 3-0 FA Cup final win against Millwall.

The winger's inspirational display was an indication of his outstanding potential, leaving Liverpool legend Alan Hansen very impressed.

Hansen wrote in a BBC Sport column: "I think the jury is still out on Cristiano Ronaldo - but there is no doubt he was the star of the FA Cup final.

"We still have to remember, of course, that the lad is only 19 years of age. Considering that, you have to say he has got massive talent."

George Best

Ronaldo caught the eye of legend George Best on debut, arguably the greatest player - before CR7, at least - to wear the No7 at United.

Best said: "Ronaldo’s first United game as a substitute in the season opener against Bolton was undoubtedly the most exciting debut performance I’ve ever seen.

“A few of my old team-mates were at the game and they compared him to me.

"There have been players who have some similarities, but this lad’s got more than anyone else, especially as he is genuinely two-footed.

"He can play on either wing, beat players with ease and put in dangerous crosses with his left or right peg.

"When was the last time you saw that? With Ronaldo and Giggsy on the pitch at the same time, opposition defenders will be petrified!"

"£12.4million seems a high price for an 18-year old, but I think it’s a snip. You are talking about a lad who, if he stays injury-free, has 15 years ahead of him in the game."

⚽ Read our Transfer news live blog for the very latest rumours, gossip and done deals