A man has been arrested after running onto the pitch during the Birmingham derby and attacking Aston Villa captain Jack Grealish, West Midlands Police have confirmed.
The Birmingham City fan entered the pitch from the home end in the Championship match, before running towards Grealish and hitting him in the head from behind, causing the midfielder to fall to the ground.
Players and stewards then contained the man before he was led away blowing kisses to fans, while being applauded by his fellow supporters.
West Midlands Police confirmed a man was later arrested.
The 23-year-old Grealish did not react to the fan, eventually getting to his feet and raising a smile during a conversation with the referee after the attack in the 12th minute at St Andrew's.
He went on to score the game's only goal in the second half as Villa claimed the 1-0 league win at the home of their arch rivals.
Asked about the attack after the game Grealish told Sky Sports: "I was just unaware at the time.
"I think we had a corner, I was walking into position and felt an arm come around my face from behind.
"There's rivalry and stuff in football, but I don't think there's any place for that in football.
"I just tried to get on with my job really and I think I did. I've scored the winner and we've come away with the three points."
Birmingham City issued a statement after the match apologising to Grealish and Villa and confirming the fan will be banned from St Andrew's for life.
The club also said it would "support any further punishment this individual may face in the eyes of the law" and pledged to review its stadium safety procedures.
A statement from Aston Villa said the club was "appalled by the disgraceful attack" adding: "A red line has been crossed by this cowardly on-field assault on a player, which is unprecedented in English football."
Following the incident a number of footballers tweeted their support for Grealish.
West Ham midfielder Declan Rice and Brighton defender Shane Duffy were quick to condemn the supporter.
Former England and Manchester United defender Gary Neville called for Birmingham City to be punished over the attack.
Neville tweeted: "The club are going have to take a huge punishment for this to act as a deterrent in the future. A Points deduction or Empty stadium for 10 games!"
The incident followed a feisty opening to the game, in which Birmingham's Maikel Kieftenbeld was booked for a badly timed foul on Grealish.
There were also clashes between fans outside the stadium before kick-off
Police had to hold back fans while at least one man was seen being treated by paramedics after suffering a head wound.
The English Football League said in a statement following the Grealish incident: "The EFL condemns the mindless actions of the individual who encroached on to the pitch at St Andrews on Sunday afternoon.
"It’s a situation no player should ever be faced with.
"In all circumstances the playing surface is for players, not supporters and those playing in the game must be able to do so safe in the knowledge they will not be subjected to this type of behaviour."
The statement from Birmingham City said: "Birmingham City Football Club would like to apologise to Jack Grealish and Aston Villa Football Club for an incident in this afternoon’s derby match.
"We deplore the behaviour of the individual who committed this act and rest assured he will be banned from St. Andrew’s for life. The club will also support any further punishment this individual may face in the eyes of the law.
"The club will be working with the relevant authorities to investigate all the circumstances and we will be reviewing our stadium safety procedures.
"What happened has no place in football or society. Jack is a Birmingham lad and regardless of club allegiance should not have been subjected to this – there are no excuses.
"Again, we apologise to Jack and all at Aston Villa Football Club."
The statement from Aston Villa added: "We trust the perpetrator will feel the full force of the law and the authorities investigate the circumstances surrounding today’s deplorable incident.
"Local rivalries are part of the fabric of the game however, as we are sure our friends at Birmingham City would agree, to have a player’s personal safety placed under such jeopardy is a serious cause for concern for the entire football community."