The most literal and logical translation (at least for a Polish brain ) is:
"The league was set up for / to favour a specific team". I asked my friend (a native speaker from the US) and he says it's correct.
But if you want to construct a sentence in which you stress the implications of this situation, you might wanna say:
a) The league (clearly) favoured a specific team.
b) The league was clearly oriented towards a specific team.
Mam nadzieje, ze to pomoglo . Pozdrawiam polskiego kibica!