An off-duty NYPD cop was arrested for beating up a retired firefighter — but he claims the former Bravest has been harassing him and his wife for years.

Detective Mike Oner, 41, was busted Tuesday for punching out Richard Estreicher, 53, but the Brooklyn cop told The Post that the incident was the result of years of abuse from the ex-FDNY man.

Oner said Estreicher started the brawl by walking in front of his car as he returned home from voting.

“He said he’s a Marine, he’s a kickboxer, and then he gets into like fighting stance,” Oner said. “He puts me in a headlock, bites my head. He’s trying to rip my eye out. He’s biting my hands like crazy. I took him down, I start punching him, and then he got bloodied up.”

Estreicher suffered a broken nose and eye socket. Oner was arrested and charged with misdemeanor assault, sources said.

After his arraignment, Oner, who identifies himself as a Turkish Muslim, said the two have been at odds since he and his wife, Dikel, moved to the neighborhood 12 years ago.

“I’m Muslim — he throws a ham and cheese sandwich [in the yard],” Oner said. “I’m Turkish — he throws a turkey sandwich. I don’t drink — he throws beer caps.”

Estreicher could not be reached for comment.