37-year-old Hansel Esparragoza of Staten Island was charged with second-degree assault, police said.
Police said Esparragoza punched Guela Levi Freeman as she was walking her dog.
Surveillance video shows the suspect walking past the woman, then he turns back and sucker punches her, knocking her out cold.
Her dog stayed beside her, while a doorman and others rushed to her aid.
Freeman suffered a fractured nose and a bruised neck.
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