Mourinho has, however, countered his many highs with a number of lows, with it in his nature to come out fighting when questions are asked of his methods and ability to deliver results.
He currently finds himself in that position at Old Trafford, after overseeing United’s worst start to a season in 26 years, and Calderon believes it is an inability to steer clear of controversy which will be concerning the Red Devils board.
The ex-Madrid supremo, who got a close look at Mourinho during his time at Santiago Bernabeu, told talkSPORT: “Undeniably his track record speaks for itself, it’s the one of a winner and a very successful coach.
“And because of that he could have had the football world at his feet, in my opinion.
“But it appears he’s obsessed with staining it with so many controversies and problems.
“And then he blames the world for everything when he loses. It’s a pity.
“His track record is very, very difficult to get and it’s something he is now staining continuously.
“I remember the great Alfredo Di Stefano [the Real Madrid legend, former player and coach], he used to tell me that a great coach could never complain about referees, injuries, bad luck or any other circumstance – that was reserves for the mediocres.
“That was very self-explanatory about what a great coach must do. It’s clear that Mourinho is having many problems, even I’m sure among his followers.
“Maybe they don’t understand what he’s doing or what he’s saying. And on top of that – the results.
“When you win, everything can be acceptable. But when you’re losing, and when you’re coaching a team so great as United, then fans can be disappointed and at the start of the season with only three points out of nine – that can be a problem.
“I don’t know what the owners think about that, but of course they must be worried.”
Others have questioned his ongoing presence, with Lee Sharpe expecting the Portuguese to be gone by Christmas and Paul Parker suggesting that he is dragging underperforming Red Devils players down with him.