Were Warrior awarded points purely on its late-round rally, this drama set in the street-fight atmosphere of mixed martial arts would be one of the year’s best.

Co-writer / director Gavin O’Connor — who knows from superior sports films — lands one gut-punch after another in the third act: Joel Edgerton scrapping against a mad Russian; Nick Nolte cementing his slot in the Best Supporting Actor Oscar race; a feral Tom Hardy fueling an insanely unsentimental climax. Indeed, Warrior boasts just enough unexpectedly terrific moments of big-ticket emotion and quiet introspection that a cliché-barraged first hour and eye-rolling plot turns feel even more disappointing. That said, this 139-minute tale of family feuds settled through fisticuffs flies by — largely on strengths of vivid fight choreography and tough-minded performances.

Hardy and Edgerton (forceful imports from England and Australia, respectively) are Tommy and Brendan, estranged brothers who reunite on the national stage of Sparta — the “Super Bowl of MMA” with a single-elimination format and a $5 million purse. Warrior wastes no time establishing MMA rules; it’s fists and feet flying in furiously different styles. Even the dinging bell of boxing is too formal for these fights — regulated only by airhorns and clapped-together wooden blocks.

As Warrior opens, Tommy returns home from a tour of duty, unexpectedly arriving on the Pittsburgh doorstep of his dad, Paddy (Nolte). Enjoy the subtleties at play here; they’re the last ones you’ll see for an hour. Tommy offers the old man a slug of hooch, catering to the alcoholism that defines Paddy. He’s there to assign blame, but not with confrontation in mind. If they can kill a bottle together, Tommy can assert that the worst parts of him came from Paddy. But when newly sober Paddy refuses, Tommy grabs his demons by the hair and drags them out. Eventually, Tommy seeks Paddy’s help with the one thing he is good at — training Tommy to get back into fighting shape for Sparta. (Tommy was a wrestling prodigy back in high school.) This won’t be a backdoor reconciliation, Tommy insists.

Meanwhile, in Philadelphia, Brendan is a beloved physics teacher. But neither that, nor the two jobs worked by his wife, Tess (Jennifer Morrison), are paying bills for them and their two daughters. And there’s also little love lost for Paddy from Brendan — who played second fiddle to Tommy even though he was no fighting slouch. Upside-down on his mortgage, Brendan turns to MMA fights in strip-club parking lots for cash and persuades a trainer pal (Frank Grillo) to prepare him for Sparta.

O’Connor places an intriguing secondary rival in Brendan’s way (a messy melee that nearly upstages the final bout). And he gets oh-so-right the music of each man’s fighting style. Tommy prefers speed-punk’s strike-first, atomic assault to make his fights last no longer than a Misfits song. Despite the film’s emphasis on Beethoven for Brendan, he’s more of a jazz guy — riding the beat until he can find the groove and force the tempo.

But Warrior’s main momentum is built upon a clash of these brotherly titans. O’Connor wisely trusts an instinct to let nothing civil or gentlemanly creep into said battle, which lives up to its cinematic hype. Brendan’s monetary motivations are predictably forthright, and Edgerton excels in a thinly written everyman role. As his face becomes a mask of sliced flesh, the actor’s charisma hits harder than his character.

That alone establishes more of a rooting interest than the script can muster up for Tommy. We eventually learn Tommy’s own admirable need for the money. But the script makes him a cipher for too long, enshrouding him in an absurd amount of mysteries and enigmas. It’s a disservice to Hardy, whose untamed-animal performance matches his physique. (Seriously, he looks like trapezius muscles with a face.) Hardy channels Brando’s brawn and Stallone’s Rocky-era vulnerability — namely in the lone pre-fight scene with Edgerton, where it’s clear Tommy regards Brendan the same way he would a guy whose picture came with the frame. (Edgerton brings his best to this scene as well, a potent powder-keg moment for both actors.)

But neither trumps Nolte’s work, the best he’s done since … hell, ever. Obsessed with Moby Dick, Paddy has his own white whale — rebuilding his family. It’s an obsession he could conquer … without himself in the picture. Paddy has no better weapon to wield than a wobbly sobriety milestone, and Nolte captures the perfect, desperate realization that this is little more than a slingshot against a Goliath-sized past of awful choices.

Brendan and Tommy aren’t bad people, but their indifference and antagonism toward Paddy speak to the terrible things he taught them. Another actor would make Paddy’s eventual moments of weakness feel perfunctory. But Nolte ensures they come off as true tragedy — Paddy’s foolish, if fatherly, attempts to identify with the monsters he’s created in his sons and in himself. His is the best supporting performance of 2011 so far.

Perhaps Warrior overreaches a bit — trying to, among its three leads, speak for an entire country rather than one neighborhood as The Fighter did. (Set in the present day, it also as yet lacks the historical context of Cinderella Man). It’s ultimately a success, but it’s too often pleasant where it could be powerful.