Chelsea are furious with assistant team coach Marco Ianni for celebrating wildly in front of Jose Mourinho, the incident which sparked a touchline melee at the end of the club’s 2-2 draw with Manchester United.

Maurizio Sarri said that he has not ruled out disciplinary action against the 32-year-old Italian coach, who was ordered to apologise to Mourinho after the 2-2 draw, levelled by Ross Barkley’s goal six minutes into time added on. It is a major embarrassment for Chelsea, for whom there is no love lost with their former manager and these are precisely the kind of incidents the club wants to avoid.

Chelsea have had an uneasy relationship with Mourinho since his second sacking in 2015: he is the club’s most successful manager but the rawness of their parting has made celebrating his achievements tricky in the last three years. Mourinho said afterwards that he accepted Ianni’s apology in the aftermath. The United manager taking the moral high ground over this episode will, in all likelihood, only add to the irritation felt at Stamford Bridge that this was an avoidable incident.

Ianni, who came to Chelsea from Napoli with Sarri, twice celebrated in close proximity to Mourinho in the aftermath of substitute Barkley’s goal. He first punched the air while looking directly at the United manager. That caught the attention of the United bench but there was no response until seconds later when Ianni trotted in front of Mourinho again and celebrated with both fists clenched, prompting the latter to try to pursue him down the tunnel.