The defending champions won two of their three games against defensive-minded teams, but questions are still being raised as Spain coach Vicente del Bosque experiments with a six-man midfield.
Spain, which will play France, England or Ukraine in the next round, may not have been convincing against Croatia on Monday, but Del Bosque says winning Euro 2008 and then the World Cup have made it difficult to please everyone.
Del Bosque says Spain's transformation into a football power has come “so quickly that we don't know how to appreciate what we really have.”