After thrashing an accommodating Ireland 4-0,holders Spain may find Croatia a tougher nut to crack when they meet in Gdansk on Monday in a game that will decide who tops Euro 2012 Group C.
A 2-2 draw would put both sides into the quarter-finals even if third-placed Italy beat Ireland and a defeat would probably mean an early flight home.
Spain played sparkling football against Ireland when the recalled Fernando Torres scored twice but the world champions are wary of a dangerous Croatia side who are unlikely to stand around watching Iberian artistry.
In midfield playmaker Luka Modric,heavily linked with a move to Manchester United,and the tournaments joint top scorer with three goals Mario Mandzukic,Croatia have the quality in key areas to cause problems for Spain.
Croatia,who have never played Spain in a competitive game and are unbeaten in open play in their last six European Championship matches,are an intrepid side. They lost to Turkey on penalties at Euro 2008 and they will be bristling with intent against a Spain side unbeaten in 16 competitive matches.
One lucky omen for Croatia is that when they played the holders at the 1996 European Championship they effectively knocked them out with a 3-0 win over Denmark inspired by Davor Suker and his infamous chip over goalkeeper Peter Schmeichel.