The Scotland international was preparing to take a corner kick during a 3-0 defeat to the west London club when he was filmed receiving the foul-mouthed outburst which has been condemned by campaigners and a former Chelsea player.
Show Racism the Red Card branded the abuse “anti-Irish and anti-Catholic racism” and “unacceptable in football and anywhere in society” while former Chelsea winger, and McGinn’s fellow Scotland international Pat Nevin, demanded an investigation into the “sectarian abuse”.
The veteran, now a media pundit, was preparing to raise the issue with club hierarchy when he attended the Champions League match with Zenit St.Petersburg, but the Blues have already moved to identify the individual involved.
A club statement said: “We are aware of a video circulating on social media showing an individual using abusive language of a sectarian nature in the crowd at Stamford Bridge on Saturday.
"Chelsea football club finds all forms of discriminatory behaviour totally unacceptable and we condemn the language used.
"The club is working to identify the person involved and will take the strongest possible action against them.
"Any supporter who was present in that area of the ground and has information that can assist the club's investigation should contact the club via our discrimination reporting line, 0207 3863355."
The match was the former Hibs midfielder’s first back at Villa after a positive covid test ruled him out of his side’s 1-1 draw with Brentford and Scotland’s 2-0 defeat to Denmark in World Cup qualifying.