Well, if you analyze it like that, then Japan has never defeated Germany and Spain before this World Cup, everything happens for the first time, but I believe that Japan is not so good to beat Croatia, their match with Spain still causes a lot of controversy. Croatia's defense is one of the best in this tournament and I wouldn't be surprised if Japan can't score a single goal. The Japanese have a lot of desires, but the Croats are much stronger than them, so I expect Croatia to win in regular time.
Croatia is a better side compared to Japan based on both team's performance in the competition. But Japan have managed to win top class teams in this competition, therefore there are possibilities that they might give Croatia a real fight. Both teams have a very solid defense that means we might have less goals in this match. I am predicting that the goal margin would not be more than two. There is also a chance that this match might be decided by a penalty shootout. I don't have a favorite team in this match, I would celebrate with any team that wins this match.