Prandelli, who made numerous chances to the team that beat Estonia 3-0 in last Friday´s UEFA EURO 2012 qualifier, said afterwards: "We have to reflect on this defeat.
"We lacked many things such as intensity and depth. We reacted late and once you are behind it is difficult to bounce back.
"These are important games and hence, it is a must to reflect on what went wrong. We had problems in attack and we were slow moving forward."
Prandelli believes that yesterday´s defeat, his second since losing to Côte d'Ivoire on his Italy coaching debut back in August, will not hinder the team.
Italy are unbeaten in EURO 2012 qualifying and lead Group C with a five-point advantage over Slovenia.
"We have done so many positive things in qualifying," Prandelli said. "We have taken important results. We have shown character and quality. I'm not worried.
"If we had to lose a game, it was better to do it in a friendly against (former Italy and current Ireland coach) Trapattoni."
Italy travel next to Faroe Islands on 2 September.