Saturday’s meeting saw Jose Mourinho take an away side to his former home for the fifth time, with plenty of scrutiny still on the United manager’s position.
And Mourinho must have feared the worst as his side trailed 1-0 at half-time after Antonio Rudiger headed the hosts in front.
But the Red Devils responded excellently in the second half, taking the lead thanks to Anthony Martial’s brace.
United were so close to seeing the game out for an impressive victory, only for substitute Ross Barkley to snatch a point for Chelsea in stoppage time.
Chelsea’s second assistant Marco Ianni celebrated the late equaliser by running past Mourinho.
After Ianni passed Mourinho a second time, the United boss ran after the Italian, sparking a touchline melee, while the players soon clashed afterwards on the pitch before the game could be restarted.