Sir Alex Ferguson is unquestionably one of the greatest managers - if not *the* greatest manager - in football history.

The Scot enjoyed unprecedented success during his remarkable 26-year spell in charge of Manchester United, winning a host of major honours including 13 Premier League titles, five FA Cups and two Champions Leagues.

During his spell at Old Trafford, Ferguson assembled several legendary teams, featuring some of the best players of the past couple of generations.

Cristiano Ronaldo, Wayne Rooney, Ryan Giggs, Paul Scholes, Eric Cantona, David Beckham, Peter Schmeichel, Roy Keane, Ruud van Nistelrooy, Rio Ferdinand, Nemanja Vidic… the list of exceptional footballers goes on and on.

However, in his 2015 book ‘Leading’, Ferguson raised eyebrows by claiming he only considered four of the players he managed at Man Utd as ‘world-class’.

"In my book there are only two world-class players playing today: Lionel Messi and Cristiano Ronaldo,” Ferguson wrote, per the Independent.

"I don't mean to demean or criticise any of the great or very good footballers who played for me during my 26-year career at United, but there were only four who were world class: Cantona, Giggs, Ronaldo and Scholes.

"And of the four Cristiano was like an ornament on the top of a Christmas tree."

Many people were surprised that Fergie only considered those four as world-class, although Beckham’s response at the time was typically class.

"I tend to agree with the manager because there are certain players that you can call world class and thankfully I played with many of them,” the former England captain told reporters.

However, Ferguson later justified his opinion during an interview with Dan Walker at Bridgewater Hall in Manchester.

“I think, as a fan or when you’re watching football matches as a young kid, I was always looking at the centre-forwards or the wingers - the players who create, make goals, score goals. That’s always been my mantra in terms of watching a game of football.

“I had some of the most fantastic footballers and I probably could have called them all world-class from time to time.

“But my final analysis, when I think about it, those four players made a fantastic difference in different periods of games and this was the reason.

“I’m not demeaning or criticising any of those great players I had - it was a privilege to have them - but don’t forget one thing: those four players never won the trophies, the team always won the trophies. We could never win it with individuals. We needed the backbone of a team - always.”

He continued: “In the last 50 Ballon d’Or awards, only two defenders have ever won it. It’s debatable what you’d call Franz Beckenbauer because I would have thought he was a playmaker of the Bayern team and the great German team.

“The only defender was [Fabio] Cannavaro. He’s the only defender who’s ever won it in 50 years, so somebody’s right - it’s all opinion, by the way.

“It’s my opinion and I think I’m qualified to do that!”

Were Cantona, Giggs, Ronaldo and Scholes the only world-class players Fergie managed at Man Utd? Have your say below.