The visitors looked to be heading for a 2-1 win only for Ross Barkley to snatch an equaliser in the sixth minute of stoppage-time.

As the Chelsea staff celebrated on the touchline, assistant coach Ianni ran past the seated Mourinho, at which point the United boss jumped to his feet to confront him and had to be held back by stewards.

After the final whistle, Mourinho went to applaud the United fans before holding up three fingers to the home support — apparently in reference to the three Premier League titles he won as Chelsea manager — after they had taunted him with chants after Barkley's leveller.

Ex-Chelsea boss Mourinho was clearly enraged by Ianni, but the Portuguese later revealed Ianni had apologised to him, and that he now considered the matter "over", but it brought one of Maurizio Sarri's backroom staff into the spotlight.

But who is Ianni?

He was appointed by Chelsea in early August, joining a team that included former Chelsea players Hilario, Carlo Cudicini and Gianfranco Zola.

Ianni, who was born in 1982, retired from football at the age of 32 and immediately turned his attention to coaching.

He spent two years on the staff of Roberto Cappellacci in his native Italy — first with Cosenza and then Campobasso — before joining Sarri at Napoli, where Ianni worked as the club's technical assistant.

In a recent interview, Ianni revealed he had "a good professional and human relationship" with Sarri.

He will hope that ensures he avoids serious punishment after the Chelsea coach stressed he had to be "very hard" on Ianni for the incident with Mourinho.