Gdansk: Spanish goalkeeper Iker Casillas showed the defending champions are not just about tiki-taka and attacking virtuosity as he produced an alert performance to help see off Croatia on Monday and ensure passage to the quarter-finals of Euro 2012.
Substitute Jesus Navas hit the late winner in a nervy 1-0 win over Croatia - who could in the event of a win have knocked the Spanish out.
"It was a really tough game but that's normal in this kind of competition," said the Real Madrid shotstopper, who comfortably fielded a speculative effort from Danijel Pranjic midway through the first half, then did well to parry an Ivan Rakitic header in the second period with the score still goalless.
"We were very nervous and that didn't make it easy. We lacked a little calm," admitted Casillas, who recognised that Spain's rivals will always up their game against the best side in the world and try to smother them.
With seven points Spain qualify as Group C winners and will now play their quarter-final in Donetsk, Ukraine, on Saturday against the Group D runners-up, likely to be England or France.
Coach Vicente del Bosque joined Casillas in admitting his men had been taken the distance in boxing parlance.
"It was a difficult, intense match," said the man who led the Furia Roja to World Cup glory in 2008.
"They got men behind the ball and stayed back and kept their shape well, only coming out on the counter-attack. Yet we had expected as much," said the former Real Madrid coach, who explained he brought on scorer Navas as well as Cesc Fabregas "to give us more variation in attack."
Navas, who replaced Fernando Torres on the hour, said he was delighted to have been able to make a significant contribution - especially in the knowledge that a Croatian goal otherwise could have sent the Spanish packing instead.
Now they instead can look forward to a meeting with either England or France, depending on which of the pair finish second in Group D.
Navas says at this stage the opponent is more or less academic.
"Any rival is complicated - they are all more or less on a level. We just have to think about ourselves but stay humble. We are really in the groove," the Sevilla star insisted despite a fairly tepid showing by recent Spanish standards.