A drunken football fan struck a female steward to the face after he was refused entry to the Liberty Stadium.
The incident took place on Swansea City's final home game of the season on May 1, as they took on Derby County.
Derby County fan Edward Dylan Price, of Aberporth, had purchased a ticket to sit in the away section of the stadium.
But the 32-year-old was refused entry to the ground by stewards because he was too intoxicated.
He was described by the prosecutor as being unsteady on his feet, falling down and unable to stand still.
He became verbally abusive towards stewards, and then struck out at one of them, striking her to the left hand side of her face using his open hand.
The incident was spotted by mounted police officers on horseback and he was arrested.
Price pleaded guilty to a count of assault by beating whilst appearing at Swansea Magistrates' Court.
The prosecutor told the court: “He had been drinking from 2pm and the incident took place around 8pm.
“He got a lift into Swansea and went to a pub near the Liberty Stadium, excited because Derby were playing Swansea.
“He’d gone to get his ticket then went back to the pub and drank more alcohol.
“He told police during interview he is an idiot when he is drunk and a near alcoholic.”
Mitigating, John Allchurch said: "The defendant is self employed as a painter decorator and lives in Aberporth.
"He is a keen Derby County supporter, his mother lives in Derby, and has followed them for some years.
"He had too much to drink and slapped one steward during the course of an argument. He fully accepts the offence.”
Price was sentenced to a 12-month community order with a nine month alcohol treatment requirement. He must also complete 10 rehabilitation activity requirement days.
He has been fined £50, must pay £50 compensation to the victim, and has been given a football banning order, meaning he cannot enter any premises with the purpose of attending a football match in England and Wales for the next three years.