A woman needed to have a head wound glued at hospital after being attacked during a night out in Stamford.
On the day he was due to stand trial, Shaun Dixon pleaded guilty to a common assault charge on the woman.
The attack took place in Silver Lane, Stamford.
Daniel Pietryka, prosecuting, told the court a police officer saw Dixon throw a “short, fast punch to the victim’s facial area”.
The officer restrained Dixon as he yelled “I’ve done nothing wrong”.
Julian Sheen, mitigating, said there was an altercation outside a club “and, unfortunately, it became violent”.
He added: “All of the parties had been drinking.”
Dixon, 22, of Sturrock Court, Grantham, was sentenced to a 12-month community order and was ordered to pay £150 compensation, a £60 surcharge and £250 costs.