Chelsea assistant coach Marco Ianni was the man who sparked the late melee against Manchester United today.
Ross Barkley turned home in the 96th minute from close range, prompting Ianni to run across Jose Mourinho's path in celebration, which angered the United manager and in-turn sparked scuffles on the sidelines and in the tunnel.
Ianni ran up to Mourinho and punched the air in front of him before making a rapid escape.
The 36-year-old was Maurizio Sarri's assistant at Napoli for two years before they both moved to Stamford Bridge this summer.
Blues defender Toni Rudiger said later: "I don't know what happened at the end, I just saw the benches were standing up and not fighting but speaking and it's emotions - it's football."