David Stoneman, 44, saw red after Wayne Rooney bagged a late goal for arch rivals United last January, a court heard.
Having struck his younger relative in the face, Stoneman then also attacked an elderly man who tried to intervene
He admitted two counts of actual bodily harm and was jailed for a year.
Recorder Kenneth Carr said: “You pleaded guilty to two offences of actual bodily harm.
“They were domestic violence offences which are treated seriously by this court. This was made more serious because of your record of offending.
“The whole purpose of a suspended sentence was to send the message domestic violence is not acceptable.
“You did comply with some of the terms of the order but not the main one, do not commit domestic violence. You did and it must be immediate custody.”
Chelmsford Crown Court heard the second victim, the victim’s mother’s boyfriend, tried to break up the violence and was punched twice in the face.
“This was an unprovoked assault on a young man in an argument over the score of a football match.”
At the time Stoneman, of Colchester, Essex, was subject to a suspended sentence following an assault on a partner while at a friend’s house.
Chelmsford Crown Court heard the family were attempting to reconcile and Stoneman had apologised.
He was jailed for eight months for each assault – which will be served concurrently – and for four more months consecutively for breaching the suspended sentence.