A Bronx drug customer knocked on a crack dealer’s door too early in the morning, sparking a fatal beatdown, police said Friday.

The customer, Hector Burgos, 69, rapped on the door of his dealer, Kiam Chelcher, 33, on Cruger Ave. near Burke Ave. around 4:45 a.m. on April 25 to buy crack, according to cops.

Chelcher, angry about the early hour, confronted Burgos, police say.

As they argued, Chelcer punched Burgos in the head and face, knocking him to the ground and causing him to hit his head, according to cops.

Burgos was taken to Jacobi Medical Center where he lingered for weeks before succumbing to from suffered during the fight, authorities said.

Both men have prior run-ins with the law.

Chelcher was paroled in November 2017 after serving more than three years in state prison for dealing drugs, records show.

Burgos, who lived a few blocks away from Chelcher, had prior arrests for drug possession, burglary and arson, police said.