A student studying policing was attacked outside a Nottingham club in a case of mistaken identity.
The victim, who is a full-time student at Derby University and was celebrating New Year's Eve in Nottingham in 2019.
He headed to Pryzm, Lower Parliament Street, with a friend and waited outside for another friend when they were approached by Xavier Smith, 23, of Standhill Road, Carlton.
Nottingham Crown Court heard Smith was agitated and repeatedly wanted to know where "Jack" was.
The victim said "I'm Jack". All of a sudden Smith punched him with a hard blow. The victim's friend moved between them to prevent more blows but Smith moved around him and delivered two blows knocking him to the ground.
The victim had concussion and described being in great pain, said Gareth Gimson, prosecuting.
When police arrived, Smith had his fists clenched, was aggressive and stood over the victim on the floor.
Smith told officers "I was protecting her" and indicated towards a female he was with. She said "you hit the wrong one, it was nothing to do with him".
Smith believed there was an incident involving the woman and he was looking for "Jack" who did it, and punched the victim instead of the other "Jack".
An X-ray on the victim showed a non-displaced fracture of the neck at the lower jaw on the left-hand side and no immediate surgical intervention was required.
The man spent some time in hospital going through various checks and was unable to fully open his mouth or bite. His speech was affected and the mechanisms of pronouncing certain words were difficult.
Smith, who had four or five drinks at home and four or five more when he was out, accepted one blow.
Mark Knowles, mitigating, said Smith was a man of good character and "bitterly regrets his behaviour on that evening to the early hours".
Smith previously pleaded guilty to assault, causing bodily harm.
Recorder Michael Auty QC said the victim did nothing wrong that evening.
He imposed a nine-month prison sentence, suspended for two years, and ordered Smith pay the man £2,000 compensation within the next three months.
