WATCH: What sparked the heated scuffle between Jose Mourinho and Chelsea's assistant coach

Club football had returned back to action over the weekend with a heavyweight clash between two Premier League giants, Chelsea, and Manchester United. Though, it didn't fail to disappoint as fans were treated to a four-goal thriller. But, it also involved an ugly incident towards the end of the game involving Manchester United manager Jose Mourinho that had grabbed all the headlines.

The Portuguese manager has tasted victory against his former employees at their home ground on just one occasion, back when he was the manager of Inter Milan. It looked like Jose Mourinho was headed for another impressive victory at Blues' fortress, but Ross Barkley had other plans.

In the build-up to the match, the former Chelsea manager had insisted that he would be on his best behavior at Stamford Bridge, a place where he has had sour memories since joining Manchester United. Well, that didn't pan out exactly as the Portuguese would have expected, as Mourinho ended up in a heated scuffle with one of Chelsea's backroom staff, which led to the security personnel needing to intervene and separate the two sides.

It all started after Chelsea midfielder Ross Barkley netted late into stoppage time to salvage a 2-2 draw after a superb Anthony Martial brace had put the Red Devils ahead. The goal sparked wild celebrations in the Chelsea dugout because they had maintained their unbeaten start to the season.

However, Chelsea assistant coach Marco Ianni took the celebrations a little too over the top as he appeared to taunt the Manchester United boss following the late equalizer. And while returning to the Chelsea dugout, Ianni further infuriated Mourinho by celebrating with a fist bump straight into his face. Here's how the drama unfolded on the touchline.

While Ianni's behavior was totally stupid and uncalled for, but it was Mourinho's reaction that left him looking immature and it also shines as a bad light on the club. However, at the post-match conference, Mourinho did admit that Ianni had apologized to him for his actions, while Chelsea manager Maurizio Sarri had also apologized for his staff member's behavior and promised that he would deal with it internally.