A Manhattan man was ruthlessly walloped during an unprovoked broad-daylight attack on the Upper West Side, police said.

According to police, the 27-year-old victim was walking in front of 13 W. 65th St. around 11:10 a.m. Friday when the assailant sauntered up, slugged him several times in the right ear and bolted.

The victim suffered multiple facial fractures, cops said. He was treated at Mount Siani West hospital and was reported in stable condition.

Surveillance video released by police shows the attacker sprinting down West 65th Street wearing a white t-shirt, khaki pants and black sneakers.

Police are asking anyone with information to contact the NYPD Crime Stoppers Hotline at 1-877-577-TIPS or online at crimestoppers.nypdonline.org.