It will be a dream match. Cristiano Ronaldo vs Lionel Messi. I don't have much concerns about Argentina. They are one of the best teams right now. But the big question is about Portugal, as they are basically a one man army led by Ronaldo. If Ronaldo is properly marked by the opponent team, then Portugal will lose the match for sure. Hardly anyone else in their team has the capability to win matches. I am a big fan of Ronaldo, but I am being realistic here. In this tournament, I don't think that Portugal's chances are very bright.
I would be happy if Portugal made it to the final (and by the way I don't consider it a one man team) but I wouldn't want Portugal to play against Argentina at any point in the tournament. After every achievement by Ronaldo or Messi, the fanboy wars flare up with renewed vigor and I'm afraid to imagine what will happen if these two teams meet at the World Cup. I would like to avoid this.