Patrick Ryan, 25, of Wolverhampton, accepted the challenge of Phillip Evans, 42, that he couldn’t knock him out.
Ryan landed one right-handed blow to the victim’s neck, causing a haemorrhage that ended his life on October 11 2015.
The two had been drinking heavily, with the victim found to be at least five times over the drink-drive limit.
Prosecuting, Paul Spratt revealed that the deceased liked to engage in “horseplay” when drinking with friends.
Shortly after the punch, Mr Evans collapsed to the floor and Ryan put him in the recovery position, threw some cold water over him and alerted a neighbour.
Divorced father of one Mr Evans was certified dead at the scene.
Ryan admitted to the charge of manslaughter for killing his friend and was jailed for three years by Judge James Burbidge QC.
Judge Burbidge said: “You delivered a swinging right-handed punch in circumstances that are accepted by the prosecution and consistent with the pathology of the case.
“The deceased was known to enjoy horseplay when drinking. He had asked at least one other person to try to knock him out on a previous occasion but that person had refused to do so, as you should have done.
“You could have punched him in another part of the body and did not need to punch him as hard as you did, but he had requested you to do so.
“You are described by others as a quiet guy who is neither aggressive nor argumentative.”