A cop fired a single shot at a Bronx man pointing a gun at him and his partner and then arrested the gunman and his buddy, who was found to be carrying a fake gun, officials said yesterday.

Sgt. Michael Raso’s shot missed Michael Rock, 28, officials said.

Raso and Sgt. Lawrence Harvey were responding to a 911 tip of two armed men near Home Street and Forest Avenue at about 10:30 p.m. Wednesday. They approached Marleik Patterson, 23, and Rock, who allegedly pulled a .357 Smith and Wesson but didn’t fire it.

Rock and Patterson were arrested on weapon-possession charges. Rock was also charged with menacing.