USA vs Germany tomorrow. USA needs to win or draw against a tough German side if they want to go through to the knockout stage.
If USA lose then they can still go through unless Ghana or Portugal win. However a win by either of them will put them on equal points to the USA and 2nd place will be decided by goal difference.
In other words the scale of each win will determine who goes to the knock out stage. If USA lose they cannot afford to get hammered and they cannot afford to have Ghana or Portugal to win by a lot of goals.