To get to Goody Petronelli’s boxing club, you must first pick your way through one of Brockton’s seedier neighborhoods, a clutter of tin-pot auto marts, sullen barrooms, shoe-box doughnut shops, and tatty hair salons. There’s a chaotic feel to the area, as if its buildings hadn’t been laid out so much as tossed from a cup. In the heat of summer, the asphalt emits a petrochemical tang that can make you weep. The air shudders with drive-by bass lines. And there is something else in the air: an undercurrent of menace, the potential for physical harm. A block from Petronelli’s gym, someone has spray-painted a calling card on the sidewalk:

V.I.

VIOLENT INDIVIDUALS

It’s no accident that Brockton — birthplace of Rocky Marciano and Marvin Hagler — bills itself as "The City of Champions." There is no more fertile ground for boxing than the blighted urban landscape, and no finer raw material than the young men who loiter within it. "[P]rizefighting," wrote Norman Mailer in his 1975 book The Fight, "offers a profession to men who might otherwise commit murder on the street."

For the past 33 years, Brockton trainer Goody Petronelli has sought to channel this killer instinct into an art form. And he’s done well. On his business card, Petronelli reveals himself as the "Sole Trainer of Marvelous Marvin Hagler." In this game, in this state, it doesn’t get much bigger than that.

Its auspicious history notwithstanding, Petronelli’s gym is not what you’d call a high-end facility. You get the sense that if every piece of duct tape were stripped away, the place would fall apart. In the main area of the gym, a half-dozen or so young men skip rope, beat the heavy bag, and bippety-bop the speed bag — with nothing more than a single fan to cool them down. The air is acrid with breath and sweat, as hot and damp as the inside of a shoe. To the rear of the gym is Petronelli’s office, a musty wreck of a room where stacks of papers compete for space with discarded gloves, dusty gum shields, and mysterious bottles and jars. On the walls are pictures of Petronelli shaking hands with Chuck Norris, Kirk Douglas, Tom Selleck.

Right now, Petronelli is in one of the gym’s two rings, mitts on his hands, inviting the thunderous blows of an enormous fighter named Kevin McBride. Petronelli is not a young man ("I’ll be 43 in three years," he says sarcastically), and he is not a big man. Next to McBride, he looks like a stick figure. As he skips around the ring, punch after punch smacking the mitts, his thick eyebrows tilt like pinball flippers, and he breathes heavily through a nose that appears to be sliding down his face. Chris Pender, Petronelli’s assistant, says he has lost teeth due to boxers’ missing the mitts. Even without such disasters, sparring with the likes of McBride looks punishing. Indeed, it’s a miracle that Petronelli’s thin arms don’t splinter under the onslaught. "Kevin’s got a hell of a punch," he says later, with some understatement.

While Petronelli and McBride spar, a few guys stand around making small talk. Among them, only one seems fully intent on the action in the ring. A few seconds earlier, the man had been double-fisting cell phones, moving about the gym as if chasing squirrels. Now he is motionless, staring up at the 29-year-old McBride with a look that falls somewhere between parental pride and religious devotion. This is Rich Cappiello; he’s a promoter, and Kevin McBride is his boy, the hinge on which his fortunes may turn. McBride may even represent the future of heavyweight boxing in Massachusetts. "I think he’s one of the best heavyweights in the US," Cappiello says. "The opportunities are going to be out of control for this kid."

It seems odd to hear Cappiello call anyone "kid." In an industry where tenure is measured in decades, the 38-year-old promoter — who has been involved in boxing for a mere seven years — is himself a stripling. And he looks the part: stocky and tan, Cappiello has dark hair cut stubble-short at the sides, and a pair of wide-set eyes that literally twinkle. He wears whiter-than-white sneakers and the sporty shorts-and-shirt ensembles of the kind favored by rap stars. Upon his right biceps is a tattoo: a pair of red boxing gloves and the words CAPPIELLO BROS. While he may not have the standing of a Don King, Cappiello has all the evangelical zeal, particularly when discussing McBride. "I want a world champion, and he’s the one to do it," he says. "I really think there’s a fire under him."

For sure, McBride is a good fighter — very big and very strong. Even with a heavy bag between you, a punch from "The Clones Colossus" (named after his hometown of Clones, Ireland) feels like being hit by a fist-size truck. While he is a friendly, open, even somewhat ingenuous young man, you wouldn’t necessarily want to get on his bad side. "I’m not a fighting man out of the ring," he says. "But I do get idiots coming up to me. If I hit them, I don’t hit with an arm, I hit with 260 pounds of muscle, flesh, blood, bone." With this, McBride’s mammoth fist whistles through the air. "I want to hit right through them," he says through gritted teeth. "I’d ... snap ... his ... neck."

So far — thank God — McBride has channeled these energies into his career. In his native Ireland (he now resides permanently in Brookline), he has been the heavyweight champion for six years. McBride also bears the distinction of having been the youngest Irishman ever — at 18 years old — to qualify for the Olympics. With experience on his side and the legendary Petronelli as his trainer, say those in his camp, the sky’s the limit. "This is your time," Cappiello coos to his protégé. And then, turning to a reporter: "He knows people are relying on him."

There is indeed an awful lot resting on this young man’s broad shoulders. A week from today, on July 26, McBride will go up against Bahamian heavyweight Raynardo Minus at a Cappiello-promoted fight at Boston’s Roxy nightclub. The fight is the last in a monthly series of televised bouts that Cappiello has been running on Fox Sports New England. A win for McBride would do a lot for the promoter’s credibility, and thus provide a great boost toward renewing the Fox contract next year — something Cappiello needs to do if he is to make good on his oft-stated promise to "bring Las Vegas–style boxing to New England."

But Minus — despite his unfortunate name — will not be a pushover. For one thing, he is an unknown quantity, which is always cause for concern. Minus is also left-handed; the last time McBride fought a southpaw, he lost. And Minus is supposed to have a punch on him: out of his 28 pro bouts, he has chalked up 14 KOs. McBride might be a favorite to win, but nothing is certain in this game. "We have to win this," says Cappiello. "If we don’t, then it’s back to the drawing board. We’re not thinking about losing. I’ve got a lot of people expecting me to do this."

But when Kevin McBride steps into the ring at the Roxy, there will be a lot more than reputations at stake. If Cappiello’s success rests in part on the success of his Great White Hope, then so too does the continued progress of local boxing. As Goody Petronelli says, "It’s guys like Richie who are keeping boxing alive in Massachusetts."