Subscribe.A fight over a little white dog left one man critically injured in Midtown when a hothead went berserk and sucker-punched the victim in the face, cops said.The attack was caught on camera and shows the suspect punching the victim in the face at 6:30 p.m. Tuesday at West 55th Street and Ninth Avenue, according to police.The victim was out with a friend who was walking the little pooch when the suspect stepped over the dog in order to pass the duo on the sidewalk, police said.The irate dog owner got into it with the suspect, asking him why he stepped over the dog, according to police.That’s when the victim jumped in and started arguing with the suspect. The hothead, believed to be in his 30s, then followed the victim down the street and threw a single punch at the victim’s face, cops said.The victim was knocked off his feet and his head smacked the ground, cops said.The video was uploaded to YouTube by a witness.The victim was rushed to New York Hospital Presbyterian Hospital, where he is listed in critical condition, according to police.The dog and its owner were not harmed.The suspect is described as 5-foot-10, 170 pounds with blond hair, police said.