Intimate domestic tragedy and the hard-hitting brutality of professional boxing collide in "Southpaw," a film that invites comparison to 2004's "Million Dollar Baby" and 2010's "The Fighter" but stands on its own as purely riveting drama. The feature writing debut of Kurt Sutter (TV's "Sons of Anarchy"), the picture casts Jake Gyllenhaal (2014's "Enemy") in a role as physically transformative as the one he played in 2014's "Nightcrawler," the shape-shifting actor trading greasy gauntness for ripped abs and lean muscles. Gyllenhaal's intensely committed dynamism meshes well with director Antoine Fuqua's (2014's "The Equalizer") uncompromising forthrightness even as the trajectory of the story leads straight into convention. Because the characters are so acutely observed and their struggles so empathetic, the ultimate familiarity of the narrative's destination hardly matters.

Light heavyweight boxing champion Billy "The Great" Hope (Jake Gyllenhaal) is riding high, going 43-and-0 and making millions per match. A product of a Hell's Kitchen orphanage, he has found a lucrative career for himself, a loving family, and a gorgeous mansion that he calls home. Wife Maureen (Rachel McAdams) is supportive, but sees how badly he gets beat up and worries that he could do irreparable damage if he continues fighting. When a heated confrontation with fellow fighter Miguel Escobar (Miguel Gómez) at a charity event ends in a calamitous accident, Billy is left grief-stricken and utterly devastated. His dire circumstances escalate from there. Undone by his hot-headed anger and progressive substance abuse, he is suspended from professional boxing after head-butting a referee, forced to foreclose on his house when his income stops cold, and temporarily loses custody of 10-year-old daughter Leila (Oona Laurence). As his unlikely new mentor, gym owner Titus 'Tick' Wills (Forest Whitaker), tells Billy, if he has any hope of reclaiming his broken life he is going to have to first look inward and fix himself.

"Southpaw" reinvents itself with each new act, ensuring that even as Fuqua and Sutter toy with different subgenres—sports flick; revenge thriller; family melodrama—the film never comes off as trite or commonplace. The opening half-hour introduces Billy, wife Maureen, and daughter Leila, living long enough with these authentically drawn characters and their familial unit that it comes as a rotten betrayal when fate cruelly steps in to try and destroy them. The key turning point—a scene of such uncommonly raw power that there is no chance of shaking it for the rest of the running time—is utterly wrenching to watch, tremendous performances and the nearly unparalleled realism of its writing harrowingly intersecting.

It shouldn't continue to come as a surprise when Jake Gyllenhaal delivers a great performance, but it still does. He is stunning here—gritty, nuanced, rough and often bruised, yet able to break the viewer's heart in a second flat. Billy can be short-tempered, an issues only exacerbated when his future is forever altered. His struggle to get ahold of his emotions, both for himself and Leila, carries the picture through its involving second half. The father-daughter relationship he shares with Leila goes through multiple complex permutations as they try to work themselves out of the dark period they are in. For Billy, it is proving to her that he is responsible and willing to do whatever he can to re-earn her trust. For Leila, it is dealing with the confusion and resentment of being taken away from her dad—an experience for which she begins to blame him. Relative newcomer Oona Laurence (who previously originated the Tony-winning title role in "Matilda: The Musical" on Broadway) is nothing short of exceptional as Leila. Beat for beat, she matches Gyllenhaal, the two of them creating a troubled but deeply loving bond free of artifice.

In sharply envisioned supporting turns, Forest Whitaker (2015's "Taken 3") is excellent as Titus Wills, a man who gives Billy a helping hand when no one else is there to provide the reality check he needs, while Naomie Harris (2012's "Skyfall") affectingly plays child services worker Angela Rivera with caring and responsibility. It is Rachel McAdams (2015's "Aloha") as the outspoken, loving Maureen, however, who perhaps makes the most haunting impact. Though her screen time is limited, she makes the most of every moment, culminating in a blunt sequence of staggeringly fallible humanity. McAdams' role is small yet pivotal, her performance nothing short of a master class.

The boxing scenes are gripping and violent in "Southpaw," each jab and sucker-punch joltingly captured by cinematographer Mauro Fiore's (2013's "Runner Runner") roving camera and edited with taut fluidity by John Refoua (2013's "Olympus Has Fallen"). They predominately bookend the story, the climactic match symbolic of so much more for Billy than the one at the start. What fits in between these segments is where the film gets its emotional vigor, a character study of a man who rose from adversity as he left his childhood behind and must now find a way to do it again in his thirties when life throttles him another crushing blow. While one key narrative thread disappointingly peters out and is never brought up again, leaving a small piece of Billy's journey unresolved, the script is otherwise an economical, tightly devised study in confident, multidimensional screenwriting. The use of Eminem's rousing song "Phenomenal" to underscore Billy's fight to reclaim the things most important to him is a welcome addition, too. "Southpaw" is grown-up filmmaking with the elegant feel of a 1970s drama, focusing on the psychology and personal struggles of human beings rather than the tidily plotted events that happen to them.