Croatia captain Luka Modric believes the team have suffered something of a World Cup hangover but he remains hopeful they can still qualify out of their UEFA Nations League group.
The beaten finalists in Russia have taken just one point – a goalless draw against England – from their first two matches.
Croatia will need to avenge their 6-0 thumping by Spain on Thursday and then beat England if they are to progress but they – and Modric – are yet to rediscover their summer form which saw them eventually lose to France in the World Cup final.
"After the World Cup, it is logical that mentally you cannot keep the same rhythm, there is a lot of intensity in little time and you pay for it," the Real Madrid midfielder told a press conference.
"We've been hit hard so far, we've all been emotionally and physically exhausted, and that's perhaps why we're not like we were in Russia.
"The Spanish and English games have been too fast for us, which is why I was not at the level, but we are in a much better situation
"We will miss some of the important players who have left us but we have replacements and in the past we have always found that we can find new players."
Spain head to Zagreb needing victory to finish top of Group Four.
Barcelona defender Jordi Alba has returned to the squad after being left out by his former coach at the Nou Camp Luis Enrique.
The left-back has spoken out about how much he had been enjoying life under new boss Ernesto Valverde and many saw his previous omission as a snub from Enrique.
"I said that because of my desire to play more minutes, because everyone wants to play more and I do not regret having said it," the 29-year-old told a press conference.
"I've always said that he helped me a lot in Barcelona. It's true that last season I did not have the minutes I wanted but I've never had any problems with him or his coaching staff.
"There have been no conversations (about it) but I hope I can stay forever."