SPOILER AHEAD!
A lot of people talking about how unrealistic it is for Brendan to win in the end. Believe me i was disappointed initially. It maybe so from a technical standpoint given that tommy had been a prodigal fighter from the start. However, the movie focuses on something more important. Eventually one will realize they both stepped off the cage as brothers once again. The pent up rage and hatred tommy had towards his brother didn't mean anything before true care and affection.
I started to think that the dad sacrificed in a way not standing by tommy's side so that the brothers could have it out and end their indifferences once and for all.
Anyway a must watch !