See it from the other side. What if your opponent started the season around the same quality as you, and put in effort to improve his team significantly? In this case, he deserves to be the favourite to win the cup. If he has used his honestly earned money to buy tokens, it is fair.
What would be not fair is if your opponent fooled the cup draw, and also used bad ways (cheating, stealing, tanking and other dishonest ways) to improve his team quality before or after the draw. Another thing that would not be fair if he had significantly more free offers than you (this is actually the case for some users in this forum).
Another thing that would be not fair is if you have this same sort of situation every season, where you are always among the lower or middle levels in the Cup batch or not among the favourites.
I have discussed more about this topic in the following posts. Moi, if you had a look at this thread, have a look at those posts.
(1) http://forum.topeleven.com/top-eleve...tml#post398757
(2) http://forum.topeleven.com/top-eleve...tml#post398771
(3) http://forum.topeleven.com/top-eleve...tml#post398778