Violent and drunk Peter Wright tracked down William Walters to a Lydney flat before punching him to the ground.
Gloucester Crown Court heard the 23-year-old left a one inch cut to Mr Walters’ head when he arrived at the home in Harrison Road, Lydney on November 2, 2013 carrying a beer bottle in his hand.
Prosecutor Lisa Hennessy said the pair had history after Wright went out with Mr Walters’ sister, Melanie.
She said Mr Walters had called him a name before Wright, of Channel View, Bulwark in Chepstow went to the flat and launched the attack.
She said he knocked on the door of the flat Mr Walters was visiting, brushed passed a man who answered the door and started punching the victim until he fell to the floor.
The prosecutor said in a victim impact statement, Mr Walters, said the scar had left him with an “embarrassing bald patch” on his head.
He said he continued to worry about running into Wright and had even not gone to a funeral to avoid him.
The court heard Wright, a dad of a 19-month-old, has previous convictions for assaulting a police officer, battery and criminal damage.
Defending Dermot Clarke said: “He takes the case very seriously and I think it is impacted to him know he is facing a custodial sentence.
“He does not go out and he does not drink anymore and that has been a big significant thing in his life.
“He does have a job offer and that is dependent on him not being incarcerated.”
Recorder Stephen Climie jailed Wright for nine months, but suspended it for two years.
He told him: “I am quite satisfied your inner core is violent in the extreme, particularly when in drink.
“You tracked down Mr Walters simply because he had made a remark towards you.
“You were incapable of simply walking away.
“If we met again and on the face of it, with your record we will, you will go to prison.”
The recorder gave him a four month curfew from 7pm to 7am and ordered he pay £200 costs, £100 victim surcharge and £100 compensation.
He ordered that Wright not contact Mr Walters or his sister for two years, directly or indirectly.