While other action stars of his generation have run gubernatorial campaigns or branched out to work with art-house directors, Sylvester Stallone has wisely stuck to what’s proven to work for him in the past, investing emotionally and financially in the franchises that have made him a star. Say what you will about Mr. Stallone, but he’s an actor who’s cannily aware of his own set of limitations. Conversely, he knows what his legacy is, and he knows how to play to his strengths. This is another way of saying that the 69-year old bruiser is aware of what people expect from him: nobody’s holding their breath for Sly to do a low-budget indie with no-name filmmakers, nor are we expecting him to venture outside his action-movie wheelhouse and open up a chain of chicken restaurants or something like that. And so the big, lovable lug sticks to the Rocky and Rambo mythologies, all while churning out ultra-violent, casually amoral “Expendables” flicks like the 80’s never ended. Looks like Sly’s plan is to ride this gravy train until the wheels fall off.

“Creed,” a new spin-off of sorts from the “Rocky” cinematic universe, (take that, Marvel!) is hardly a radical revision of the Palookaville ethos that made the original film one of the most successful of all time. It is also far from a mere retread: for the umpteenth entry in a long-running series about a blue-collar slugger and his ongoing quest for redemption, “Creed” feels unusually vital and even occasionally suggests the dawn of something completely new. This is a ridiculous notion, of course, since the end result ends up feeling so familiar. Still, “Creed” is acted with grace and conviction, with none of the half-assed sleepwalking that you occasionally see in sequels where contractual obligations are the primary motivating factor for the cast. It is also nimbly directed by Ryan Coogler in only his second feature-length effort, and though I somehow doubt “Creed” will break the mold — as some of its more ardent and hyperbolic supporters would have you believe (seriously, have we seen a confidently-directed traditional sports drama garner THIS many four-star reviews?) — but hey, there was literally no reason to expect this movie to be very good at all, let alone as good as it ends up being.

When “Creed” opens, we see young Adonis “Donnie” Creed, son of Rocky’s nemesis Apollo Creed, duking it out with another hardscrabble youth at a grim-looking juvenile detention center. Fast forward a couple years later and Adonis has grown into a prideful, volatile young man with something to prove. Played with immense gravitas and charisma by Michael B. Jordan, grown-up Donnie has forsaken his decidedly white-collar vocation (an interesting touch in a formula film like this) at a securities firm to engage in vicious hand-to-hand brawls in some of Tijuana, Mexico’s less reputable venues. Fighting isn’t just his passion: it’s practically all he wants to do.

Our hero’s quest for glory eventually leads him to modern-day Philadelphia, painted here as a drab, depleted urban landscape filled with abandoned, run-down storefronts, ratty gyms and shabby one-story homes. It is here that Adonis confronts his father Apollo’s onetime rival Rocky Balboa, (hey Sly!) who now owns an old-school Italian eatery charmingly named after Adrian, his one true love (there are “Rocky” easter eggs aplenty for fans here, including a gut-wrenching final shot that may induce waterworks in the franchise faithful). The remainder of the plot will be familiar to anyone who’s seen at least one boxing movie from the last fifty or so years of cinema, but the style in which “Creed” unfolds feels bold and fresh, and sometimes even uncommonly personal.

A great deal of this can be attributed to director Coogler, now in his second collaboration with leading man Jordan in the wake of his harrowing, tense, facts-based drama “Fruitvale Station”. On the evidence of his first two films, Coogler is a director who is committed to the immediacy and authenticity of every moment. It’s a quality that goes a long way towards selling some of the script’s more heavy-handed beats, including Rocky’s third-act battle with a terminal illness and Donnie’s only moderately convincing romance with a tough local beauty named Bianca (“Dear White People’s” Tessa Thompson).

He also possesses a previously unseen propensity for grandiosity, and he acquits himself to the film’s rousing, violent set pieces with energy to spare. It’s also nice to see the fights themselves unfold in long, patient takes wherein all the action is fluid and serves a greater narrative purpose. It’s the opposite of the jumpy, impatient filmmaking style seen in this year’s other boxing drama, the inferior “Southpaw”. And Coogler has found the perfect leading man in Jordan, whose ferocious screen presence occasionally suggests a younger, less gentle Will Smith. Jordan’s range as a performer is hardly off the charts, but purely taken as an on-screen presence, he’s unforgettable: coiled with intensity and teeming with quiet waves of purpose and feeling.

Which brings us back to Stallone, who in this film is more funny, endearing and relaxed than he’s perhaps ever been. He doesn’t look as though he’s striving to recapture the thuggish luster of his younger years, nor does he appear to be revising his iconic screen persona. On the contrary, Sly seems to be at peace with his place in the annals of pop culture mythology, more so now than ever. Whether he’s dancing like a sweet old grandma to his young protégé’s disbelief or imbuing the standard ringside pump-up speech with a depth of sincerity that we don’t often see in these movies, this is some of the best work of Stallone’s career. All that talk about him snagging a Best Supporting nod for his work here? Believe it. The rest of “Creed” turns out to be just as surprising: an old-fashioned sports drama that displays the benefits of keeping it close to the vest. B