A young man died in a Queens bar brawl early Thanksgiving morning, police said.

John McGee and a second man were squabbling as they walked outside The Gaslight on Queens Boulevard in Sunnyside around 3:45 a.m.

The suspect cold-cocked McGee, 21, in the head, causing him to fall to the ground and suffer a cardiac episode, according to cops.

The attacker ran off, leaving McGee laid out on the pavement.

First responders rushed the man to Elmhurst Hospital Center, but he could not be saved.