Quite possibly they were of similar quality at season start. The Cup is that way, though. If you are a very good team for your level you will be facing higher level teams. This is what makes the Cup the hardest challenge, and also makes it different than Champs League. If it was all the same level players, it would be a clone of CL.

Believe me, I know it feels like punishment for having a good team, I never make it far in Cup, I feel like Aue facing Munich.