As Real Madrid continue to be linked with a summer move for Manchester United goalkeeper David de Gea, the pressure builds on club captain Iker Casillas ahead of the latest Madrid derby…

David de Gea called Iker Casillas “the best keeper in the world” in 2011. The respect was mutual. “He will soon be fighting for my place,” said Casillas at the time. “He's a great keeper. We have to take care of him because he is the future. He will pension us all off.” Four years on and it seems the Real Madrid and Spain No.1 was more right than he knew.

The reports of Real’s interest in bringing De Gea back to the Spanish capital simply won’t go away. Spanish journalist Josep Pedrerol even told TV channel La Sexta that a summer move had been agreed for the Manchester United goalkeeper whose contract has a little over a year left to run. “David de Gea is clear,” said Pedrerol. “He wants to be the Real Madrid goalkeeper.”

It’s just the latest issue that Casillas has had to deal with in what’s been a turbulent few years for the 33-year-old. The midweek Madrid derby against Atletico puts him back in the spotlight after being booed by the Bernabeu crowd on his previous Champions League appearance in the stadium against Schalke. It’s become a familiar phenomenon for the erstwhile ‘Saint Iker’.

When Jose Mourinho first dropped Casillas in December 2012 it was initially seen as Jose Mourinho playing politics, but when Diego Lopez established himself for an extended period of time the water was muddied. “He had nothing against Iker,” Lopez told Canal+ recently. “I wasn't his nanny boy. If my form dropped, so would I be.”

Crisis of confidence

The experience could have spurred Casillas on but instead the doubts about his waning form have remained, mushrooming into a full-blown crisis of confidence. The player even admitted in a FIFA interviewed that he “cried, suffered, felt bad and had nights where I slept little, if at all” during his absence from the starting line-up.

Carlo Ancelotti retained Lopez as his La Liga goalkeeper last season and, while Casillas did get the glory of La Decima, his performances were not wholly convincing. Indeed, he was fortunate to escape the blame in the Lisbon final when at fault for Diego Godin’s opener – a goal only cancelled out in the dying moments of normal time – and followed up with a dismal World Cup showing.

Error prone? Iker Casillas is the only goalkeeper remaining in this year’s Champions League who has made an error leading to a goal in the competition this season.

According to Opta, Casillas is the only goalkeeper remaining in this year’s Champions League who has made an error leading to a goal. The comparison with De Gea is not favourable. In fact, Casillas has made more errors leading to shots in the last two Champions League seasons (20 games in total) than De Gea has made in his last 89 Premier League appearances dating back to 2012.

Reactive goalkeeper

It’s not all damning for Casillas. He actually boasts a superior save percentage to De Gea inside the box in those same competitions. “Casillas is at the moment and what he has perhaps always been: a very good reactive goalkeeper but not so good proactively,” Guillem Balague told Sky Sports earlier this season. It’s De Gea who has worked hard to turn himself into the more commanding keeper.

Casillas is at the moment and what he has perhaps always been: a very good reactive goalkeeper but not so good proactively. Guillem Balague

It all makes Casillas’s position in the Real Madrid goalmouth increasingly precarious. “There are no reasons to leave Real Madrid,” he told Marca in December. “I still want to win many titles with this jersey.” But with United boss Louis van Gaal refusing to rule out De Gea’s departure – “in football, everything is possible” – Casillas’s hopes could yet prove forlorn.

With Lopez having departed for Milan, Casillas is now battling against Keylor Navas, the man who beat Thibaut Courtois to last season’s La Liga goalkeeper of the year award. While Casillas recently went six weeks without a win, Navas played in the only victory that interspersed that sequence and following it up with another against Eibar earlier this month, keeping clean sheets on both occasions.

Manchester United legend Peter Schmeichel gives his verdict on David de Gea Manchester United legend Peter Schmeichel gives his verdict on David de Gea

If that challenge is winnable, the threat of De Gea has the air of inevitability first forecast by Casillas all those years ago. Perhaps the template comes from the national team. Casillas’s misjudgement of a free-kick against Slovakia in October contributed to Spain’s first qualifying defeat in eight years and saw him dropped in favour of De Gea – a move backed by 86 per cent of voters in a Marca poll.

'Sweet transition'

But Vicente del Bosque has looked to phase in the move, restoring Casillas for the next three games prior to giving De Gea another chance against the Netherlands last month, describing the changeover as a “sweet transition” as the younger man is ushered in. Not everyone is convinced.

Iker Casillas and David de Gea have been sharing goalkeeping duties for Spain

“In every aspect De Gea should be the goalkeeper now,” said former Manchester United striker and Revista de la Liga regular Terry Gibson. “But how do you go about doing it? Is Casillas going to be the second choice? If Real Madrid want a new goalkeeper then Casillas will have to go, and if Spain want a new goalkeeper then it will have to be retirement for Casillas from international football.”

It seems that the pension beckons for Iker Casillas, but there is still time for him to shape the terms of the departure. Victory in the Madrid derby on Wednesday night would move him a step nearer to becoming the first captain to retain the European Cup in a quarter of a century and the first in the Champions League era to win the trophy four times with the same club.

Achieve that and it would ensure that a Real Madrid legend ends the campaign drinking in the adulation at the Cibeles fountain rather than enduring the boos of the Bernabeu ringing in his ears. It’s clear which scenario Iker Casillas deserves, but Diego Simeone’s Atletico Madrid don’t do sentiment. Casillas must rediscover the assurance of old – and be the goalkeeper of 2011 - if he’s to prevail.

Watch Real Madrid v Atletico Madrid live on Sky Sports 1 HD from 7.00pm this Wednesday