Thirty-three-year-old Danny Grieve of Athol Court, Jedburgh, pleaded guilty to assaulting a man by punching him on the head and knocking him to the ground to his severe injury on June 5, 2022.
Prosecutor India McLean said the victim along with others had been socialising in the Vine Night Club and were all drinking alcohol and Grieve was also present.
She explained that a night club worker noted was aware of Grieve looking for trouble.
The fiscal continued: "At 2am closing time the complainer and his friends exited the night club and went into the Square. The accused approached him from behind and punched him to the ground.
"The victim has got up and attempted to leave but the accused has punched him again which resulted in knocking a tooth out."
Ms McLean said that following this around 30 people started fighting in the Square with police having to intervene. In addition to the broken tooth, the victim suffered facial swelling.
Grieve was spoken to and cautioned and charged and made no reply.
Sheriff Peter Paterson said: "This is obviously a serious matter."
He called for a Criminal Justice Social Work Report and a Restriction of Liberty Order assessment to be prepared "to see if there is any alternative to a custodial sentence."
Sentence was deferred until February 26.