Colombia have scored more and conceded less than Brazil so far, while Brazil have come through the tougher tests. I can't call it, either way, it could be a showdown between the two countries' young stars, a storming game from a less fashionable name, penalties, anything. I'm just so excited.
One left-field prediction I will make is that the young star for whoever gets through will go on to get the golden boot - i.e., James Rodriguez or Neymar. I know everyone is predicting Messi, but they have as good a chance as any, IMO.