A spectator stormed the pitch during Birmingham City's clash with Aston Villa at St Andrew's on Sunday, throwing punches at Villa midfielder Jack Grealish.
With just ten minutes on the clock during the match, a fan jumped the barricade and ran onto the pitch, attacking Grealish before being dragged from the pitch by security.
News of the incident came from BBC Sport, who discussed the incident during their live commentary of the game.
They wrote: "A supporter runs on from the stand behind and attacks Grealish from behind with a swinging arm. Idiot. Absolutely shocking scenes there as that man is led away very swiftly to be dealt with by the authorities. Absolutely no need for that."
Speaking on BBC West Midlands, former Birmingham City midfielder Darren Carter condemned the fans' actions, adding: "It is a rivalry and you get passionate but you should never come on to the pitch. That is diabolical behaviour."
The two sides are separated by just two miles in Birmingham, and the Second City Derby is always a fiercely contested affair. Both teams currently find themselves trailing the top six in the Championship, with Sunday's match set to be a crucial one for either side's play-off aspirations.
Grealish has been a vital part of Villa's side this season. He has made 23 appearances for the Villains this season, racking up three goals and four assists, including a stunning strike against Derby County in his last game.