The brawl at The Glass House in Stourbridge started with some pushing, but quickly escalated into a fight between 17-year-old John Brogan and Kieron Lavelle, Wolverhampton Crown Court heard.
The 33-year-old ended up on the ground under the teenager while also being battered by a third man. In desperation, he bit into the ear of Mr Brogan and refused to let go, causing serious injury and lifetime scarring.
"The injured party described the pain as awful, " said Mr Gareth Walters, prosecuting. "He kept asking the defendant to let go but he would not."
Lavelle left after the club's security staff broke up the fight but was arrested by police soon afterwards. A passing patrol had been alerted by the victim whose blood was found on the clothing of the attacker. Both men required hospital treatment.
Mr Brogan's ear was partially torn off and badly damaged in the attack, said Mr Walters who concluded: "The wound required a lot of stitches and there is permanent scarring."
The victim had been to a boxing match and another club before reaching the Glass House, the court was told.
Mr Michael Anning, defending, said Lavelle was guilty of using 'excessive self defence.'
He explained: "At the time this took place he was under one man and another man was repeatedly, and quite severely, punching him.
"There was a strong element of two against one and the others were getting the better of him. This is a significant mitigating factor. He accepts that the bite, although prompted by self defence, was excessive."
Lavelle from Olympian Court, Kidderminster, who had previous convictions for affray, wounding, battery and assault, admitted wounding during the May 12 brawl and was jailed for two years three months.
Recorder John Edwards told him: "You have written a letter to me in which you say you realise it is time you had a hard look at your life and are confident that you can turn things around. But you have a bad record for violence and the landlord of the premises where this happened said you were locked onto the ear and would not let go of Mr Brogan.
"He had just gone for an evening out to witness a white collar boxing match when he got in this scrap with you during which you displayed extreme violence."
Lavelle was jailed for two years and three months.