An NYPD employee was busted early Saturday after he socked another man in the face during a Staten Island bar fight — in an effort to defend a woman who didn’t even need his help, cops said.

Dominick Longo, 22, an NYPD police attendant, thought his 21-year-old victim was harassing a woman at the Play Sports Bar in Annadale around 12:45 a.m. — so he punched him, leaving him with a bloody nose, police said.

Despite Longo’s efforts, the woman told him she didn’t need his assistance after all, cops said.

Longo, who monitors jail cells at precinct stationhouses, was charged with assault and harassment. He was issued a desk appearance ticket.