Cristiano Ronaldo was an unstoppable force of nature at Real Madrid.

While there's no denying the class that Ronaldo brought to Manchester United and Juventus, I think we can all agree that the serial Ballon d'Or winner enjoyed the best years of his career in Spain.

Besides, it's staggering to think that Ronaldo amassed 450 strikes in 438 games for Los Blancos, surpassing Alfredo Di Stéfano's record and bagging four Champions League trophies.

Ronaldo's Real Madrid days

And although Ronaldo bowed out of the Spanish capital in a blaze of glory, we can't get away from the fact that his peak years came during his early-to-mid seasons with the European giants.

There's an argument to be had that Ronaldo played his best football for Real under the watch of Carlo Ancelotti but if that's not your bag, then Jose Mourinho is the coach who takes that title.

After all, Ronaldo helped himself to an astonishing 168 goals in just 164 matches alongside the 'Special One', winning the La Liga crown and a Copa del Rey trophy for good measure.

Ronaldo and Mourinho's collaboration

However, for all of Ronaldo's breath-taking performances under Mourinho, it wasn't until the final months of their Real collaboration that the partnership contributed to a Ballon d'Or victory.

Besides, 2010 to 2013 was very much the era of Lionel Messi domination, winning France Football's prestigious prize four times on the bounce, but Mourinho couldn't have disagreed with it more.

Now, that might sound obvious considering Mourinho was managing Ronaldo at the time, but rest assured that the Portuguese made a convincing argument about the two legends in 2012.

'It's harder to be Ronaldo than Messi'

In fact, there's good reason to think that Mourinho's fascinating throughline on why Ronaldo has a harder task than Messi might still be relevant to the GOAT debate almost a decade later.

According to the Independent, Mourinho told A Bola: "It would be a crime for Cristiano to not win the Ballon d'Or. And I keep saying it's harder to be Cristiano than Lionel Messi.

"I'll tell you: Messi grew up in the team he plays for now; with the teammates he plays with now. Cristiano came from England to a team that was losing. He had to grow up in the past two years with this team in construction.

"One plays centre forward and the other is a winger. Messi is about 50 metres closer to the goal and has less defensive work. How can a winger score the same amount of goals as a centre forward does?

"This is a winger that defends, a winger that ends the game in the 94th minute with a sprint to chase Pedro in a goal scoring position. This is a player that, in dead ball situations, comes 20 times to the defensive area.

"He is very important to the defensive set up. He is a player that isn't protected by nothing or nobody. It's much, much harder."

It seems fitting that a man famed for 'parking the bus' in the interest of tactical security would, well, park a bus when it came to his own arguments because he makes a pretty convincing case here.

And while it's worth adding a pinch of salt for some underlying Portuguese and Real Madrid bias, there's only so much you can bat away the opinion of one of modern football's greatest minds.