Few films commit to the darkness as, uh, thoroughly as Thoroughbreds and even fewer remain entertaining within the heavy subject matter.

Funny and violent — sometimes simultaneously — the remarkably assured debut from writer/director Cory Finley upends teen film conventions and raises technical standards for the oft-rushed subgenre.

Unsettling yet amusing from the start, the story finds Lily (Anya Taylor-Joy, Split) tutoring her former friend Amanda (Olivia Cooke, Me and Earl and the Dying Girl) for the SATs in the wake of the latter’s psychotic episode that’s kept her away from school and society overall.

Largely a showcase for the self-professed “unfeeling” Amanda to suck other characters in with her poker face and acerbic observations or quickly gain the upper hand over those ill-equipped to contend with her on a reasonable level, Thoroughbreds follows its misanthropic heart once Lily drops her guard and sees the world through her old chum’s filter.

Miserable under the tyrannical rule of her rich stepfather Mark (Paul Sparks, Midnight Special), in whose mansion she and her mom (Kaili Vernoff, Hulu’s The Path) live, Lily allows Amanda’s half-joking — who’s to say? — suggestion of killing him to take root.

Upon encountering low-level drug dealer Tim (the late, great Anton Yelchin, sharp once more in his final film), Lily thinks she’s found someone to take care of the problem, but things naturally don’t go to plan, yielding even more intriguing actions and reactions in the process.

Buoying the lead trio’s engaging dynamic are well-planned framing and camera movements that occasionally resemble a low-budget yet sharp looking homage to The Shining, plus well-timed edits and uses of foley to comic and horrific effects.

Within the impeccable visuals are some problematic male gazing issues, or at least wardrobe issues for the two teenage girls, but even that suggestiveness feels part of Thoroughbreds’ masterful command of gallows humor.

Consistently poking fun at the wealthy, the film earns big laughs from the absurdity of Amanda playing a game of giant chess against herself as well as Tim’s pronouncements of future success if given 5-10 years — and the consequences he’ll have to face in his ritz new neighborhood as a registered sex offender, something the girls don’t hesitate to address.

Like most black comedies, it’s not something that exactly encourages repeat viewings on a regular basis, but the initial watch makes for a wild time at the movies and the lean work seems destined to warrant a revisit before too long.

Grade: B-plus. Rated R. Now playing at Biltmore Grande and the Fine Arts Theatre

(Photo: Focus Features)