First of all, a Southpaw is a left-handed boxer who leads with the right. Utilizing the southpaw move is basically what Jake Gyllenhaal's character has to do to separate himself in a prominent boxing match.
Based on everything I just wrote, you can probably tell that the story like isn't anything earth-shattering and the plot is fairly predictable. So Southpaw is certainly not a unique boxing movie, by any means. If you're looking for something more creative, go with Million Dollar Baby. But Southpaw does have one thing on its side: Jake Gyllenhaal. He's the type of actor who completely embodies a character. He's always believable and he plays crazy quite well. You could have made this movie about croquet and Jake would still be hella intense and weird. It's what he does and it works.
Southpaw could have used a bit more creativity and, oddly enough, a bit more punch in the writing. Jake's particular brand of crazy can only do so much for a movie that clocks it at over two hours. But I do recommend that you download Eminem's Phenomenal.