Cristiano Ronaldo has proven himself up against some of the world's toughest defences across his illustrious career.
Whether it's tangling with Gerard Pique, Carles Puyol, Thiago Silva or Nemanja Vidic, you can guarantee that the Manchester United star has gotten the better of them at one point or another.
Besides, it comes with the territory of being the greatest goalscorer in football history and it's no slight on those legendary centre-backs that Ronaldo has made them look silly from time to time.
Ronaldo vs world-class defenders
However, it's no only natural that Ronaldo didn't find it quite so easy to get the better of world-class defences when he was honing his skills as a young player at United.
And many of the defenders that are now widely accepted as some of the greatest of all time were at the peak of their powers when Ronaldo was evolving into the footballing machine that we know today.
In many ways, Ronaldo was arguably wrought and bruised into the goalscoring giant that would go on to win five Ballon d'Or titles by way of competing with legendary defenders of eras gone by.
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AC Milan 1-0 Man Utd (2005)
In fact, those passing dynamics were perfectly on display when United locked horns with AC Milan during a Champions League round of 16 tie in the 2004/05 campaign.
The Red Devils were dumped out of the competition after losing 1-0 to the Italians - who eventually lost the final under famous circumstances against Liverpool - both at the San Siro and Old Trafford.
And the return leg in northern Italy was a significant one for the young Ronaldo because it pitted him against the legendary back four of Cafu, Alessandro Nesta, Jaap Stam and Paolo Maldini.
Ronaldo vs Cafu, Nesta, Stam, Maldini
It doesn't get much better than that, does it? However, Ronaldo wasn't without quality alongside him, too, because the Portuguese shared a starting XI with Ruud van Nistelrooy and Wayne Rooney.
However, to cut a long story short, Ronaldo came out on the wrong side of a dominant defensive display from AC Milan's all-stars with the then 20-year-old being given a tough lesson at the top.
And few clips from the game demonstrate that fact better than when Ronaldo tried to dazzle Cafu with a series of step-overs only to be mugged off by a brilliant tackle that you can check out here:
Ronaldo's individual highlights
It wasn't an isolated incident either because Ronaldo's individual highlights show that Maldini gave him a seriously tough time on right flank, reducing him to ambitious strikes from long range.
Ronaldo did manage to launch a few crosses into Milan's penalty area, but almost all of them were met by the forehead of Stam and Nesta. Check out how United's starlet fared down below:
Ronaldo loses his temper
And the frustration clearly got the better of Ronaldo because he was also involved in a heated clash with Cafu, which had to be broken up by the referee and can be enjoyed below, having been tackled once again.
A steep learning curve
So, it really goes to show that even a player destined to become one of the greatest athletes of all time can't necessarily hack it against arguably the strongest back four that football has ever seen.
But make no mistake that it's hardly a criticism of Ronaldo because no doubt tough games like the 1-0 defeat at San Siro helped to toughen him up into the footballing machine of his peak years.
Besides, there can be no greater challenge to thicken your skin in the world of football than Cafu, Maldini, Nesta, Stam, Clarence Seedorf and Gennaro Gattuso cutting you down every 10 seconds.News Now - Sport News