Football legends such as Madrid's own Alfredo Di Stefano and Barca's Johan Cruyff have described Mourinho's style as anti-football - the polar opposite of Pep Guardiola's beautiful brand of tiki-taka.
But tennis star Rafael Nadal, an unabashed Real Madrid supporter, voiced his belief that the under-fire Portuguese coach did not deserve such criticism.
"Football is not all [about] playing nice," said the World No. 1, according to Marca.
"After a 5-0 [loss to Barcelona earlier in the season] Mourinho had to make a change, it is as though I lost 6-0, 6-0 against an opponent," Nadal added.
Although Nadal admitted he appreciated the attacking footballing philosophy employed by Guardiola, he felt it was unfair to compare the two teams.
"Madrid has undergone many changes in recent years and it has been difficult to develop a playing system," he reasoned.
Nadal's footballing insights did not go so far as to predict the outcome of Wednesday's Copa del Rey final.
"Madrid can win the Cup and the Champions League, and Barca, who are without a doubt the favourite, can win it all. [Real Madrid and Barcelona] are the two best teams in the world..."
Criticisms of Mourinho’s tactics stemmed from the fact that he deployed three defensive midfielders in Xabi Alonso, Pepe and Sami Khedira to stifle the likes of Lionel Messi and Andres Iniesta.