A party goer attacked another man after guests were asked to leave a birthday bash.
An argument broke out when the other man allegedly caused Daniel Ancuta to spill his drink and then refused to apologise.
Ancuta threw a punch which sent the victim falling backwards, banging his head and suffering a cut.
The 19-year-old, of Warley Road, Blackpool, admitted assault occasioning actual bodily harm when he appeared at Preston Crown Court.
He was placed on a 12-month community order which will involve 24 hours at an attendance centre, plus a two-month curfew, to operate from 8pm-7am at night.
The incident happened at a property in Vicarage Lane, Blackpool, where the victim’s girlfriend had had a birthday party in February.
Clare Thomas, prosecuting, said Ancuta was one of those invited.
It was suggested that he spoke to the victim’s girlfriend inappropriately on a few occasions and wanted to speak to her in private.
Towards midnight she tried to get people to leave.
The defendant followed her into the front room and was said to have turned the lights off and shut the door.
Ancuta pleaded guilty on the basis that the victim kicked the door open, hitting him and causing him to spill his drink.
The victim refused to give an apology and there was an argument.
Ancuta punched out because he felt threatened, the court was told.
The victim suffered a cut to the right hand side of the head which was later glued.
He also had a chipped front tooth and bruising.
Ancuta told police the victim had begun swearing at him and had grabbed a mop, trying to hit him with it.
At that point he struck out.
John Woodward, defending, said Ancuta had felt threatened.
“He believed he was about to be hit with the mop.
“He accepts culpability on the basis of excessive self defence.
“It was one punch and resulted in the other male banging his head on some skirting board or a wall.”