Chico took a wrong turn into a Little Havana alley, near his cousin’s house, when a sixth-grader lying in wait knocked him out with brass knuckles. Then he pulled out a razor blade.

“He cut me,” said Dennis “Chico” Reyes, 15, of Allapattah, who lifted his T-shirt to show the long scar. “He wanted me to join a gang and I told him no.”

Reyes felt his life was in danger and way beyond the scope of a turning to a parent, a teacher or even the police because of the “G-code” or a street rule he explained keeps teens from telling on others. Reyes needed help from a “G” or someone who knows the streets, so he reached out to Rene “Level” Martinez, a former backyard brawler he saw on YouTube from a computer at the library.

Martinez, who gets thousands of fan emails each month, noted Reyes’ persistence as the reason he decided to call and then meet with the teen.

“There are a lot of at-risk Chicos out there struggling with nowhere to turn,” said Martinez, who became an Internet sensation a few years ago after he knocked out a martial arts expert at Kevin “Kimbo Slice” Ferguson’s backyard in Perrine. “I want to turn negatives into positives.”

Martinez, 37, said he can get through to teens like Reyes — in ways most adults cannot — as he shared the same struggles as a teen, which led him to join a gang and run afoul of the law. He was arrested 21 times from 1990 to 1998, but not since then, according to Miami-Dade court records.

Now in his search for a more purposeful life, Martinez, who now fights professionally, recently opened his “Level `Em MMA Academy” in a West Kendall business park to reach out to more teens he deems “at-risk.” Last week, at the gym’s grand opening, about 100 people watched Martinez spar with students inside a custom octagon cage just like the ones used on cable fight shows.

With its cement walls and row of punching bags and pull bars, the no-frills warehouse is gritty and tough. But there is a gentle side, too, that reaches out to parents and kids.

“We want to be Power Rangers,” said Briana Perez, 5, who looks forward to taking classes at the gym with her big sister, Alyssa, 8, and her father, Jorge, an auto mechanic who wants to stay in shape.

“If and when the time comes, I want my daughters to be able to defend themselves,” said Jorge Perez.

Programs have been custom designed for kids ages 3 and up with a focus on academics, thanks to Martinez’s mother, Ileana Vasquez.

“We also have programs for adults and offer discounts to police, fire and military,” said Vasquez, as she manned the gym’s membership booth. “But students are the main focus.”

Vasquez does community outreach with Martinez, and they have given lectures at nearby schools like Miami Dade College about how to use social media to improve your brand. Martinez, who lives in Perrine, has used the Internet to promote his own clothing line and music label.

After a few months of training, Reyes said that bullies up to a few years older now leave him alone. The discipline has allowed him to focus on a different battle: school.

“Level told me that the only way I can stay in this program is if I keep my grades up,” said Reyes, as he threw a series of punishing blows at Martinez inside the cage.

“And that’s a struggle I can live with.”