The victim was stabbed repeatedly in his torso at W. 139th St. and Lenox Ave at 9:05 a.m. and died at Harlem Hospital at 9:45 a.m.
The alleged attacker, 32, was picked up by cops canvassing the area. Neither man’s name was immediately released.
No weapon was recovered, and it wasn’t clear what sparked the attack.
The stabbing occurred in a NYPD Impact Zone, an area typically patrolled by rookie officers because it is considered a crime hot spot.