A 62-year-old man died three days after an attacker delivered a punch that sent him face-first onto the concrete in Brooklyn, cops said Wednesday.

Lenford Johnson was on Nostrand Avenue near Tilden Avenue in Flatbush around 3:10 a.m. Nov. 7 when three men accosted him during either an attempted robbery or a dispute, authorities said.

One of the men punched him in the face, causing him to fall to the ground, fracturing his skull, police said.

Johnson, who lived only blocks from the scene, was taken to the Kings County Hospital Center, where he was pronounced dead on Nov. 10.

No one had been arrested by Wednesday morning.