A baffled Zlatko Dalic acknowledged his Croatia side were not "a shadow of the team" who reached the World Cup final in July as they suffered the country's heaviest ever defeat as they were trounced 6-0 by Spain in their first competitive match since the tournament in Russia.
Saul Niguez headed in a cross by Dani Carvajal in the 24th minute, then Marco Asensio hit two remarkable long-range shots in the 33rd and 35th to give Luis Enrique's team a comfortable lead before half time.
His second strike bounced off the post and the back of goalkeeper Lovre Kalinic, who was awarded an own goal.
Asensio, who was not among the starters against England, also set up Rodrigo's goal early in the second half with a perfect through ball behind the defence.
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Sergio Ramos, one of the remaining members of Spain's golden generation, added the fifth goal with a header off a corner kick in the 57th minute, and Isco closed the scoring in the 70th after another set up by Asensio.
Croatia fell apart after defender Sime Vrsaljko had to be substituted due to an injury just minutes before Spain's first goal.
"We were very good in the first 20 minutes, we had three clear chances, but after that and Vrsaljko's injury, we vanished from the pitch," Dalic, the former Al Ain manager, said. "We were not even a shadow of the team from before."
The result continued Luis Enrique's promising start to life as Spain manager, with the result coming after they had beaten England 2-1 on Saturday.
"They had chances in the beginning but after that we were clearly superior," Enrique said. "It's difficult to find anything to criticise after a match played at this level. Our attitude has been commendable."