The story is a familiar one. A love affair between player and manager, soured by on-pitch disputes and made worse by the huge personalities on each side of the divide, eventually making the split irreconcilable. It is particularly familiar for the ever-caustic Jose Mourinho, who looks set to cement his latest football feud in the shape of unsettled Manchester United star Paul Pogba.
A mystery illness that kept Pogba on the sidelines at the weekend as the reported storm reached its peak, followed by his benching in Wednesday's Champions League draw away to Sevilla – although as the fates would have it he would nevertheless play almost 80 minutes thanks to Ander Herrera's injury misfortune – have only heightened the tension between the pair. And those wondering what this might mean for the midfielder's future need only ask Iker Casillas what happens when one strays onto the Special One's bad side.
When Mourinho arrived at Real Madrid the goalkeeper was nothing less than a living Bernabeu legend. Newly crowned as world champion following Spain's World Cup victory in 2010, Casillas was at his peak at the age of 30, and already boasted three Liga titles, two Champions Leagues and, for good measure, a European Championship winners medal in his bulging trophy case.
It should have been a match made in heaven: the world's best shot-stopper working alongside a coach famous for constructing rock-solid defences wherever he stepped. And to begin with the marriage went swimmingly. After a debut season that served as a transition while Pep Guardiola's Barcelona captivated the world with their magic, Madrid hit back with their first Liga crown in four years with victory in 2011-12.
Inspired by a miserly defence commanded by Casillas and a free-scoring attack made up of Cristiano Ronaldo, Gonzalo Higuain and Karim Benzema, the Merengue lost just twice in a season that yielded 100 points. But even at that point, a seemingly innocuous olive branch offered by the goalkeeper to Madrid's fiercest rivals had already marked the start of a feud that would cast a shadow over the club.
Back in August 2011, Casillas and Xavi shared a common concern. “We have to fix this,” the two captains decided, as clashes between Real Madrid and Barcelona – with Mourinho often in the thick of the action – were becoming increasingly bitter occasions. For the sake of the Spain national team, and through a series of friendly phone calls, the pair negotiated an uneasy peace for the upcoming Supercopa. They were widely lauded for their diplomacy, for the most part: Mourinho, however, took grave exception to the pact, and considered Casillas' actions as a sign of weakness and a betrayal of the hermetic, "us against the world" dressing room atmosphere which is such a hallmark of his management style.
While that breach of Mourinho's omerta strained relations, Casillas himself points to the 2012-13 season as the real breaking point. “Our relationship started to fall apart when the team was not playing well,” he explained in an interview held after his Madrid exit.
“You know how it is, when things go well we are all tall, handsome and have great hair; when things go badly the problems begin to arise. In the end, that is when you have to stand together.”
Weathering storms, however, has never been a trait of the Special One, who prefers the quick fix. As results in 2012-13 failed to match the heights of the previous season and Tito Vilanova's Barca waltzed to the title, Casillas was singled out as the source of Madrid's malaise. Just like his predecessor as captain Raul, sold off to Schalke in Mourinho's very first days at the club, the goalkeeper found his legendary status no protection against the vagaries of the coach's decisions.
The final breakdown came in January 2013. Diego Lopez was drafted in from Sevilla and immediately got the nod as Madrid's starting keeper, with Casillas relegated to the bench for the first time since he broke into the Merengue XI as a teenager. The decision did nothing to improve results, as Barca walked La Liga by 15 points and for good measure lifted the Champions League; Casillas, meanwhile, watched on forlorn while his replacement picked the ball out of the net four times as Robert Lewandowski and Dortmund put his beloved side to the sword.
“When you spend so long in the same team, people start to get bored of you,” a crushed Casillas explained to El Mundo in 2015 as, two years after Mourinho's exit, he prepared to leave his boyhood idols for Porto. The goalkeeper regained his starting spot in Carlo Ancelotti's second season, but nevertheless left through the back door at the Santiago Bernabeu and still holding a grudge against his old foe: “This was an inheritance from the previous era.”
Ultimately both Mourinho and Casillas lost their battle of wills, each man slinking out of Madrid far from the glory they had once tasted. The lesson is there for the manager, and Pogba too if he cares to look back at the history books. Mourinho's feuds have a tendency to hurt everyone involved, and the midfielder may well be mistaken if he believes that whatever problem affecting the pair will simply fade away. If this frosty relationship cannot be repaired lightning might just strike twice, leaving not just Mourinho and Pogba but also the whole of Manchester United on the losing side.