It began as a marriage of convenience between a coach hungry to establish himself at the top of his sport and a club determined to put the brakes on the runaway success of its archrival.
For Jose Mourinho, coaching Real Madrid added a major notch to his career, having previously led Inter Milan to the 2010 Champions League title and guiding Chelsea to six trophies in three years.
Madrid president Florentino Perez banked heavily on Mourinho having the qualities required to counter Pep Guardiola's stinging victories with Barcelona and also the strength of character to sort out a squad encumbered with "galactico'' trappings but lacking any silverware.
Mourinho had proved his Champions League pedigree early by winning the trophy with Porto in 2004, aged just 41. Perez set aside considerations that Mourinho's fascination with defensive tactics might grate with his team's tradition of overwhelming opponents through attacking prowess.
Two-and-a-half seasons later, the honeymoon is in tatters and the talk is that it was never a love match anyway.
Spain's media has claimed the Portuguese doesn't understand the "stateliness'' of Madrid and the reverence it deserves.
As evidence they point to the disrespect Mourinho showed to his position by poking (then assistant coach) Tito Vilanova in the eye during a melee in August 2011, and also to how he has criticized his own players in public for not showing the guts and commitment to win matches.
Mourinho was scathing after Madrid's 2-1 loss at Celta Vigo in the Copa del Rey last Wednesday.
"There are players who have disappointed me,'' he said. "(Some) didn't want to play because it was cold, raining.''
Perez showed unusual warmth as he quickly stepped up to defend him on that occasion.
"We have the best coach in the world, with an impressive track record,'' Perez said Sunday. "From here, Jose Mourinho, I give you my acknowledgment, my confidence in your work and my affection.''
That was before Sunday's 2-2 draw against lowly Espanyol at the Santiago Bernabeu, a result that left Madrid in third place in the league, 13 points behind leader Barcelona after 16 matches, not to mention facing possible elimination from the Copa after a first-leg defeat.
Mourinho conceded it was "practically impossible'' for his side to retain the Spanish league title pried from Guardiola's grip last season.
"The distance is too great to achieve the league,'' he said after the draw, words that Perez responded to rapidly.
"Madrid's sporting principles are never to give up, however difficult the challenge,'' the president said Monday.
The atmosphere in Madrid's dressing room has been tense, leading sports newspapers Marca and As have repeatedly reported in recent weeks. Rumors that French club Paris Saint-Germain may be trying to sign Mourinho have caused unease, as have unsubstantiated but unceasing speculation that the Portuguese coach really wants to end up at Manchester United.
Mourinho has never hidden his admiration for the English Premier League since beginning work as a translator, then assistant coach, to Bobby Robson at Lisbon in 1992 and then Barcelona.
The Portuguese has tried to quash rumors of his departure.
"No, it's not true,'' Mourinho snapped at a news conference Saturday before a French journalist had even been able to pronounce the first two words of his question.
With the journalist about to speak again, Mourinho interjected that in May he had signed a new four-year contract to remain as Madrid coach until 2016, quashing the Frenchman's curiosity about any possible link with PSG.
But last season's success, in which Madrid finished with 100 points and 121 goals and Guardiola left the sport for a break, has been all but forgotten.
Barcelona has eclipsed Mourinho's squad, making it look flat-footed. The media have been quick to lay the blame on Mourinho's methods.
"His choking style of leadership, his persistent and obsessive defiance, have finally exhausted his players,'' said sports columnist Alfredo Relano in As.
The problem for Perez and fans is a lack of ideas as to who could replace Mourinho. A random question flung at Joachim Loew last week about his chances of taking the job was immediately dismissed by the German national coach.
"I do not care about the rumors. This is just speculation,'' Loew said to German Television station Sport1. "Jose Mourinho has a contract until 2016. I have a contract until 2014.''
Despite the criticism and doubt that Mourinho has engendered, there is still great respect for his ability, as Perez's words demonstrated. No trophy is more precious to Madrid than the Champions League, and hope still remains there.
The Spanish media grudgingly asked on Monday if Mourinho had "the pulse'' to turn Madrid's situation around.
"He still can, but much will have to change,'' Relano said.