The result saw Italy reach the final 16, but Spalletti was angry with their flat performance.
“When games are decided like this at the end, it all becomes more emotional, as nobody believed any more, but the players did. They kept their heads clear, risked very little despite being left with only three defenders on the field,” Spalletti told Sky Italia.
“I can only congratulate them for their reaction and dealing with such an attacking line-up on the pitch.
“There’s no denying it, we were below our usual level in the first half. If we don’t create very much, we’re not going to score very much. You can see we were thinking about bringing a result home, without really believing that we needed a win. It was involuntary, but I expect more from my players, because they show it in flashes.
“These games are difficult because Croatia are a very strong team, they have a lot of experience at this level and can cause problems for anyone they face.”
He also snapped: “We were absolutely not prudent. If the limitation is that we struggle to play out from the back with simple balls, then we will struggle with any line-up or any tactical system that we use.
“In the first half, we lost the ball in ways we absolutely cannot afford to do. That’s not prudence. If we don’t play with quality, if we do the basics and nothing more, then we will struggle.
“It was not about the system, we were too timid in the first half, but the system was irrelevant compared to the attitude and quality seen on the field.”