“The Enforcer” is filmed-proof that the difference between a C-movie and a straight-up, watchable B-picture is Antonio Banderas. Ask first-time director Richard Hughes. He’ll tell you.

The Aussie Hughes was behind the camera for this tale of finding a single virtue in Miami’s vice, a moral ex-con who makes it his business to save a street kid kidnapped into the sex trade.

It captures the lurid underbelly of M-town — the movie version of it, anyway — and promotes it in a mentor-mentee story of “collecting” work and the hard men who do it. The saving grace of this latest spin on “The Debt Collector” trope is that this time, Banderas is the star, not the C-movie king who made two tales with that title.

Banderas is “Cuda,” nicknamed that thanks to the ’68 Plymouth Barracuda he cruises South Beach, in. He’s tougher than tough, but he’s over 50, fresh out of the joint, and the boss (Kate Bosworth, expanding her repertoire and getting away with it) has him train a new recruit whom he also uses as “muscle.”

Stray (Mohean Aria, not bad) is a yard fighter who picks up cash in bareknuckle brawls in the toughest part of town. He goes for a ride, does his part, and finds himself at a driving range in the middle of the night.

“Goooolf,” Banderas/Cuda purrs between swings, “is about patience, timing, keeping your COOL. Obviously, you lack all of these qualities.”

That’s about it as far as “training day” goes. Because Cuda has this teen daughter who isn’t interested in reconnecting after his prison stint. So he takes on another “stray,” 15 year-old Billie (Zolee Griggs) from Atlanta.

When his protection doesn’t save her from trafficking, Cuda must track her down and have his moment of truth with boss Estelle and a drugs-and-sex-trafficking underling played gangsta-to-the-hilt by the rapper 2 Chainz.

The picture begins with the young Stray’s story, and doesn’t totally lose track of him throughout, but he’s the sideshow here. There are cliches, continuity issues and the odd attempted grace note — the ex-con in the classic muscle car staring, in disbelief, at the drifting car culture that blew up while he was in prison.

Mostly, “Enforcer” is content to be just a somewhat efficient march through a formula. So I’m not saying it’s all that good.

What I am saying is that Banderas, filmed and showcased like the great leading man and simmering man of action he still embodies, makes “The Enforcer” worth watching all by himself. Again, ask director Hughes. He knows where the money is and he never strays far from it, or him, in this just-lean-enough debt collector thriller.

Rating:  R for strong/bloody violence, language throughout, sexual content, nudity and drug use.

Cast: Antonio Banderas Mohean Aria, Zolee Griggs, 2 Chainz, Alexis Ren and Kate Bosworth

Credits: Directed by Richard Hughes, scripted by W. Peter Iliff. A Screen Media release.

Running time: 1:31