The Real Madrid captain is well aware that Vicente del Bosque's team are now universally accepted as the team to beat, following their triumphs at Euro 2008 and the 2010 World Cup
Iker Casillas believes that defending the European Championship will prove far more difficult than winning it for the first time because Spain no longer have the element of surprise on their side.
While the Spanish were considered one of the strongest teams in the world going into Euro 2008, their propensity for underachievement meant that many pundits doubted whether they had the requisite bottle to win a major international trophy.
However, after their triumph in Switzerland and Austria, and subsequent success at the 2010 World Cup in South Africa, Spain now travel to Poland and Ukraine as the clear favourites to prevail.
"The problem now is that we are not going to the Euros in the same way as we did four years ago," Casillas admitted to reporters on Monday.
"We were known then, but we were able to gradually surprise people and went on to win the tournament. But now everyone in football knows about Spain."
However, Luis Aragones, the man who masterminded Spain's 2008 triumph, believes that Vicente del Bosque's troops can make history this summer.
"I was optimistic at the World Cup and I am again now," the 73-year-old coach declared. "They are trying to become the only team to win a third consecutive tournament and it will be tremendously difficult.
"But I think Del Bosque and the team are going to do well. We are favourites and I think we are going to retain it."
Spain have been drawn in the same group as Italy, Republic of Ireland and Croatia at Euro 2012.