Sir Alex Ferguson knows better than most about the quality of Cristiano Ronaldo.

Ronaldo's rise at Man Utd

The iconic manager, who is arguably the greatest that football has ever seen, was one of the masterminds behind Manchester United's decision to procure the young Portuguese in 2003.

And it turned out to be a move that changed the landscape of the beautiful game forever with Ronaldo evolving into the goal-scoring and Ballon d'Or-winning machine that we know today.

However, if anything has worked against Ronaldo in his astonishing career then it's the fact that it has pretty much run parallel with another one of the greatest players in history: Lionel Messi.

Erling Haaland to Chelsea STALLS (Football Terrace)

Inescapable Ronaldo vs Messi debate

As such, you can hardly close your eyes and swing a stick on Twitter without bumping into a thread, video or statistical analysis on which of the two has been the superior player of their generation.

It's a fascinating debate on which everybody has an opinion and power to the fans, by the way, but you'd be hard-pressed to argue that they have better insight than Ferguson himself.

Sure, the United icon is inevitably biased towards his former player, but make no mistake that the Scot is acutely aware of the damage that Messi did to the Red Devils at the back end of his career.

Ferguson on Messi vs Ronaldo

Besides, you'd be mad to claim that Ferguson doesn't give credit where credit is due when it comes to Messi and co because he named 2011 Barcelona as toughest team that he ever played against.

So, downplay Ferguson's opinion at your peril and although he's cast his thoughts on Ronaldo vs Messi more than once, we're inclined to think that one of his most recent solutions is the best.

Speaking during an appearance at the K Club in Kildare in 2016, Ferguson was keen to highlight what he considered to be the difference between Ronaldo and Messi with fantastic reasoning.

'Ronaldo could play for Stockport'

According to the Independent, the great United coach mused: “It’s interesting to me that we hear so much about two players these days: Ronaldo and Messi.

“Now don’t get me wrong, Messi is a fantastic player, it’s like he’s wearing slippers when he controls the ball. But here, for me, is the difference. Messi is a Barcelona player.

“But Ronaldo could play for Stockport County and score a hat-trick. He has everything.

"He can shoot with both feet, head the ball, he’s as brave as a lion, and here’s something else people overlook.

“During my time at Manchester United I was lucky enough to have a lot of people who put in countless extra hours to get better.

"Gary Neville turned himself from an average footballer into a wonderful one because of his work ethic, as did David Beckham.

"But Ronaldo used to completely exhaust himself, and still does. He just wanted to be the best in the world.”

Is Ronaldo the more complete footballer?

It's a train of thought that not only has Ferguson pedalled in the past, but one that seems to be shared by many of Ronaldo's backers who point out that he's allegedly the more complete player.

We'll leave you to draw your own conclusions from that, but we'll perhaps never truly know how correct or not Ferguson is with Messi seemingly set to see out the rest of his club career with Barca.

ENTER GIVEAWAY

Either way, though, it's certainly hard to contest that Ronaldo is better in the air and is more two-footed, while the astonishing evidence supporting his superhuman work ethic can't be ignored.

But doesn't it just speak volumes that the near mythic opinion of arguably the greatest manager that football has ever seen doesn't even come close to ending the Messi vs Ronaldo debate?