Spain midfielder Xabi Alonso has called on his teammates to improve on their Croatia performance if they want to win Euro 2012.
The reigning European and World champions are gunning for a historic third consecutive major international trophy, but they could only stutter to a 1-0 win over Croatia in their final group game.
The Euro 2008 champions still qualified top of Group C, but the Real Madrid star wants to see an improved showing in the quarter-finals.
Speaking after the Croatia match, Alonso said: "We have achieved great things in the not-so-distant past but we also struggled a lot, you cannot forget that.
"If we want to repeat that success, it'll definitely be another hard task."
Sevilla and Spain winger Jesus Navas grabbed the only goal of the game in the 87th minute, but Vicente Del Bosque's side were only one goal away from elimination at one stage.
And Alonso revealed the Spanish team anticipated a tough test against a talented Croatia side.
"We knew it wasn't going to be easy because Croatia are a good team and had chances to go through, too," said Alonso. "We managed to keep a clean sheet despite their efforts, and at the end of the day, the goal calmed our nerves."
Croatia midfielder Ivan Rakitic had an excellent chance to put his country ahead mid-way through the second-half after wonderful work by Tottenham star Luka Modric. But the centre-midfielder, who also plays for Sevilla, could only plant his header straight at Spain's relieved goalkeeper Iker Casillas. And despite enjoying the majority of possession, Spain lacked their usual cutting edge in the final third.
Del Bosque's team face the runners-up of Group D in the quarter-finals, as they bid to defend their 2008 crown won in Austria and Switzerland. That year they faced Germany in the final, and once again the two European heavyweights are favourites to contest the tournament showpiece in Kiev on July 1.