You’ve got to hand it to a sports movie that doesn’t much bother with scores and shows very little on-field action. (Or at least I do.) Of course, “Rudi o Cursi” isn’t really a sports movie at all. It’s about a pair of none-too-bright soccer-playing half-brothers from the boonies, to be sure, but it’s really more about sibling rivalry, family dynamics and the business of big-time athletics than it is about the game itself.

It also represents a reunion for Diego Luna and Gael Garcia Bernal, the stars of Alfonso Cuaron’s crossover hit “Y Tu Mama Tambien” (2001). In this picture from Alfonso’s writer-director brother Carlos, Luna and Bernal are Beto and Tato, stepbrothers who work on as banana plantation somewhere in rural Mexico and strut their stuff on local football fields in their spare time. Tato’s the more ambitious of the two, dreaming of a career as a singer despite a distinct lack of talent, but when peripatetic agent Baton (Guillermo Francella) spots the duo, he recognizes diamonds in the rough. Since he has room for but one new client, though, he takes only Tato to Mexico City, where the kid, as a result of raw talent and a bit of carefully-applied cash, becomes an overnight sensation. Beto soon follows in his footsteps, however, and before long the two have buried the hatchet and become roomies as well as stars—Beto nicknamed Rudo (Tough) and Tato Cursi (Corny)—though on different teams.

But their happiness is not to last. Tato goes wild with celebrity, getting involved with a sultry TV star and becoming more interested in an obviously doomed effort to become a pop singing star. Beto, on the other hand, is introduced to big-time gambling and soon finds himself in trouble with some very unsavory types. Needless to say, things go downhill fast, and it all leads up to an inevitable final game in which champion scorer Tato winds up facing champion goalie Beto, with an outcome that will determine the rest of the brothers’ lives.

“Rudo y Cursi” could be dismissed as little more than Mexican versions of the horrid Will Ferrell-John C. Reilly comedy “Step Brothers.” Tato and Beto are only marginally brighter—or shall we say less clueless than their American counterparts. But Cuaron doesn’t take their story nearly as far into the region of dumb slapstick as “Step Brothers.” There remains a kernel of authenticity to the plot. And that’s strengthened by Bernal and Luna; they bring a measure of genuine grit to their characters, who wind up deeply flawed and even foolish, but still recognizable human beings rather than mere clowns. The same is true of the rest of the cast. Francella, for instance, might have turned Baton into a purely farcical manipulator, but he comes across as more than that.

The credit’s due not merely to the cast, of course, but to Cuaron, whose script may make use of genre conventions but gives them a distinctive twist. That’s apparent in his treatment of the game action, which he shows not directly, but for the most part through reaction shots of the spectators. It might seem just a comic trick, but it’s actually much more effective than trying to fashion scenes in which the actors, however dexterous they might be, could show off real soccer star quality. And the result is funnier than direct coverage would be.

There’s nothing technically extraordinary about the movie, but the frayed visuals and slightly skuzzy quality of Adam Kimmel’s cinematography actually suit the picture. Even the “glamorous” moments have a properly garish quality that reeks of phoniness.

There’s no depth to “Rudo y Cursi,” but Bernal and Luna make the surface formula more fun than you might expect.