To say that Argentina doesn't impress is an under-statement. Their midfield, defense and goal-keeper are at mediocre level and far away from the standards of a 1/4 finals of the World Cup. They were punished twice by Nigeria, but in fact, they deserved to concede goals against both Iran and Switzerland - especially the Swiss created a plethora of excellent scoring chances, most of them with active contribution by Argentina defense.
Also, I don't like neither the interaction among the attacking people in Argentina's squad, nor their slow and boring rhythm. It seems that they leave all to Messi, but to be fair, despite a few moments of brilliance, he doesn't seem to play his best football at this tournament and for big parts of the game he has very little influence on the events on the pitch.
Belgium is the most balanced team in this tournament, with plenty of class in each line, starting from probably the best goal-keeper in the world and finishing with two very promising strikers like Lukaku and Origi.Belgians are gradually finding their form and had their best game of the Mondial against the USA, when the Red Devils deserved to win with huge margin.
All in all, I don't see where the advantage of Argentina should come from. They continue to play crap and very dispirited football, and apart from several super-stars, the rest of the team is of very questionable quality (including their coach). Belgium is full with belief and getting into their best form. Psychological advantage is entirely with Belgium as they have already achieved their goal in this tournament and everything more they can get here is over-achievement for them, unlike Argentina, for which failing for one more World Cup to pass the 1/4 finals will be considered a failure.
