Paul Mitchell brought “shame upon himself and his family” after the assault during Sunday’s derby match, his lawyer says.
A Birmingham City fan has been jailed for attacking Aston Villa footballer Jack Grealish on the pitch.
Paul Mitchell, 27, pleaded guilty at Birmingham Magistrates’ Court to assault and a charge of encroaching on to the playing surface.
He was sentenced to 14 weeks in jail.
Grealish was punched by Mitchell less than 10 minutes into Sunday’s derby match at Birmingham City’s St Andrew’s ground.
Despite the assault, the Villa captain went on to score the game’s only goal.
In a statement read to the court, Grealish, 23, said: “I cannot help but feel how lucky I was in this incident.
“It could have so much worse had the supporter had some sort of weapon.”
Prosecutor Jonathan Purser told the court that Grealish felt “lasting pain” but suffered no “substantial injury” from the punch to his jaw.
The footballer was surprised at how easily Mitchell was able to run on to the pitch, Mr Purser added.
Mitchell – a father-of-one – claims not to have been drunk when he launched the on-field assault before he was wrestled off the playing surface by stewards.
The pub worker, from Rubery in Worcestershire, allegedly told police he thought Grealish “was a k***”.
Vaughn Whistance, Mitchell’s lawyer, told the court on Monday: “He cannot explain what came over him yesterday morning. His initial foolish intention was to just go onto the pitch and whip up the crowd.
“He has brought shame upon himself and his family… and the football club he has supported since he was a child.
“He apologises to Aston Villa and in particular Jack Grealish for his terrible behaviour.
“He is certainly remorseful today.”
Mr Whistance said that Mitchell’s family had been receiving abuse online after the incident and had been forced to move.
The defendant’s mother broke down in tears as she sat with his father in the public gallery during the hearing.
Birmingham City have already said Mitchell will be banned for life from their stadium.
:: Meanwhile, a man has been charged with assault after an Arsenal fan ran on to the pitch at the Emirates Stadium and allegedly shoved Manchester United defender Chris Smalling.
Gary Cooper, 30, of Styventon Place in Chertsey, Surrey, was arrested on Sunday and will appear at Highbury Corner Magistrates’ Court in north London on Friday.
He has been charged with common assault and going on to the playing area, the Metropolitan Police said.