This guy ought to register his hands as lethal weapons.

A tough-as-nails jiu-jitsu expert made such quick work of a purse snatcher in Central Park Thursday, a group of other would-be crime-stoppers could only stand by and watch his martial artistry.

Gaston Cavalleri, a 32-year-old British tourist, used his skills to hold 16-year-old accused crook Charles Williams until cops came.

Unfortunately for Williams, Cavalleri had studied jiu-jitsu at one of the world’s best schools in Brazil — meaning he needed about as much help as Batman would have needed from a group of Gothamites.

“You’re going to have to wait until the police arrive,” Cavalleri told Williams after the teen yelled, “Let me go! I can’t breathe!”

The excitement began just before 8:30 p.m., when Williams allegedly ran off with a bag containing cellphones, credit cards, and other items from two German tourists who’d been laying out in one of the park’s grassy spots.

Cavalleri chased down the suspect near the entrance to Wollman Rink and tackled him.

Other good Samaritans also ran after the suspect, but Cavalleri had the situation well in hand.

“I didn’t want to hurt him. I wanted to secure him, so he wouldn’t run away,” said the park hero, who studied jiu-jitsu at the highly respected Gracie school.

“One of the moves I had him in was a bit tight around his neck,” Cavalleri said. “He said he was having trouble breathing. So after a while, I put him in a different move.”

Williams promised he wouldn’t run away, but Cavalleri kept him tightly gripped with his legs.

“I had him controlled,” Cavalleri said.

Officers were on the scene within minutes.

Williams is charged with grand larceny and criminal possession of stolen property.

Cavalleri, who grew up poor in British public housing, caught a lucky break when his mother won a lottery prize worth more than $35 million.

Cavalleri, who’ s just written a book about his life called “Gaston’s Secret,” arrived in New York three weeks ago.

His Central Park experience hasn’t soured him on the city or its people.

“People are friendly,” he said. “It’s one of the friendliest places I’ve been to, actually.”

Additional reporting by Kirstan Conley