Bosses clash over Conte's 'humiliating' gestures to the crowd
Jose Mourinho accused Antonio Conte of trying to humiliate him during his nightmare return to Stamford Bridge.
And it was not just Mourinho who did not take the defeat well. A member of his staff ignored the outstretched hand of Conte at the final whistle and was involved in a heated argument in the tunnel.
The flashpoint between the two managers came at the final whistle after Conte had gesticulated for the Stamford Bridge crowd to start singing for their team with time running out.
Speaking in Italian, Mourinho used the full-time handshake to tell Conte that his cheerleading had been an attempt to humiliate him in front of his former fans.
Conte denied that was his motivation, insisting he felt his team deserved the adulation of the crowd. Both Mourinho and Conte refused to confirm what was said, but neither denied the version of events that was put to them.
Conte said: "I think private conversations must remain private.
"I think that, today, it was right to call our fans in a moment I was listening only to the supporters of Manchester United at 4-0. So I called the fans to give the players a great clap after this kind of performance.
"We live with emotions. If you want to cut the emotions, we can stay at home and I will change jobs.
"It's important for our fans to push in every moment of the game. When the players deserve it after this performance, it's right to receive a great clap from the fans."
Mourinho said: "You know me. I spoke to Conte, not to you. I'm not the kind of guy to come here and share with you things I don't want to share. I have no comment."
Ironically, Mourinho called for the Stamford Bridge crowd to be louder on numerous occasions during both of his spells at the club.
The Chelsea fans left it until their team were four goals ahead to start a rendition of 'Jose Mourinho' in tribute to the club's most successful manager and the 53-year-old added: "I didn't feel it [the reaction from the crowd]. I was in the game.
"For sure it was not negative. It had no reason to be. What would they have against me, or me against them? Nothing. Everything was calm."
Mourinho team's performance was not as bad as the scoreline suggests.
"It started badly after a few seconds," Mourinho said. "You come with a strategy, so you cannot concede a goal in the way we did.
"We were coming to have an offensive approach, we wanted to create chances. We showed that after the 1-0.
"The second and the third were counter-attack goals. If we score a goal like we almost did for the 2-1 the game would be different.
"It is one of those days when you give the advantage to opponents by doing nothing."
Mourinho accepted, however, that individual errors by the likes of Daley Blind, Chris Smalling and Paul Pogba proved decisive in United's defeat.
"We made incredible defensive mistakes, individual mistakes and you pay for that," he said. "In terms of points, we got zero points, we lose three points.
"We are six points from the top, three from the top four, we now need to win matches. We need to win our matches now, which are not easy.
"We need to win to close that gap, after these last three matches, we made two out of nine, we now need points.
"But the team played well, if we can delete the defensive mistakes we made. Thibaut Courtois had more work than De Gea, their defenders had more work than my defenders."
United face Manchester City at Old Trafford in the League Cup on Wednesday with Mourinho admitting that defender Eric Bailly will miss the game with a potentially serious knee injury.
"He is injured and I'm afraid he's badly injured," Mourinho said. "In his knee, in the ligament area. He feels that it is really bad."
Chelsea's players were clearly delighted to beat their old boss and took the opportunity to rub his nose in it by posting pictures on social media of the entire team celebrating in the dressing room.
Having seen his Chelsea side suffer defeat to Liverpool and Arsenal in their first two meetings with fellow title contenders, Conte stressed the importance of this victory.
Despite being prematurely written out of the race in some quarters, Chelsea now sit in fourth, just one point off Manchester City.
"This game was very important for our ambition," he said. "After two defeats against two great teams like Liverpool and Arsenal, it was very important to have a good answer and to win against a very strong team.
"After this type of win, it usually increases your confidence.
"You trust more in the work. I think this is the most important piece. The three points, good, because now we are in a good position in the table but we must continue.
"Now we must be focused on Wednesday because there is another important, tough game against West Ham. It's important to celebrate this evening, but then to start to focus on another game."