At his best - and he was at his best for a decade plus - Iker Casillas was unparalleled. He was a peerless shot-stopper. However, it was his excellence in all facets of the game that allowed him to straddle the changing demands placed upon goalkeepers at the turn of the century, and Casillas, like Gianluigi Buffon, represents the last bastion of keeper who gave equal weight to the more traditional aspects of keeping and the modern obsession with playmaking from deep.
Granted, Casillas had a difficult end to his career. That is without question. Yet, for a decade plus, he was the best goalkeeper in the world. In fact, his decline seemed so pronounced partly due to the level of brilliance that preceded it.
That brilliance saw Casillas win every honour at domestic, European and international level. What sets Casillas apart from his contemporaries - including Buffon - were the crucial interventions that set the platform for those successes. Casillas thrived in pressure situations in matches crucial to the aforementioned success. So consistent were these interventions and at times improbable - to the point they were termed divine - he earned and deserved the nickname Saint Iker.
That moniker was first bestowed upon him at the 2002 World Cup where he saved two penalties in the shootout against Ireland in the round of 16. The then 22-year-old was unable to prevent his team getting knocked out on penalties to South Korea in the next round, but he had firmly established himself as Spain's number one, a role he would fulfil for a decade plus.
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Casillas was not first choice ahead of the tournament but an unfortunate injury involving an aftershave bottle and a severed tendon meant Santi Cañizares missed out. However, Casillas was far from inexperienced, he was already a two-time Champions League winner having collected that trophy in 2000 with a win against Valencia and again in 2002 where some inspired keeping - after his introduction as a substitute - guided Madrid to a ninth Champions League crown after Zinedine Zidane's memorable volley had given Madrid a 2-1 advantage against Bayer Leverkusen.
Casillas' ability to make key contributions marked his career at international level too. The two penalties he saved against Italy in their quarter-final of the Euros in 2008 were crucial in setting in motion an era of unprecedented dominance that ran for six years. It is easy to forget that up until that point Spain were viewed as international football's serial underachievers. And it was in football's biggest match - the World Cup final - where Casillas staged his most crucial intervention of a career marked by crucial interventions, saving expertly in a one-on-one situation from Arjen Robben as the Dutchman bore down on him during a fraught and sometimes brutal final. Casillas once again set the foundation for his team to win.
At club level Casillas added a third Champions League title in 2014 but the toxicity of the Jose Mourinho era weighed heavily on Saint Iker, and he would leave the club in 2015 having won five Liga titles, two Copa del Rey, three Supercopa de Espana, two UEFA Super Cups, and one FIFA Club World Cup. He was a brilliant goalkeeper in his own right, but it is the pure weight of success that elevates him above other esteemed goalkeepers; it is what makes Casillas' candidacy so strong.
He straddled eras where the art of keeping changed dramatically but managed to reign supreme in both. That is genuine greatness.