If any further proof was needed of just how important Sunday's Manchester derby was, just take a look at what happened in the tunnel after the game.

The walls of Old Trafford must have seen some sights over the years, but rarely has a scene of such aggression and tension been witnessed.

Mikel Arteta was given medical treatment for a cut he suffered, while Jose Mourinho had milk, water, and empty plastic bottles thrown in his direction.

The picture that is emerging is not one of a harmless scuffle - in fact, this sounds like a lot more than the kind of handbags we're used to seeing on the pitch.

Both City and United will now have to give statements ahead of an FA investigation.

The game itself, which of course shouldn't be overshadowed given its significance to the title race, ended 2-1 to the visitors and prompted joyous celebrations in the away dressing room.

Mourinho reportedly took exception to the manner in which the City players were behaving, as they were allegedly blaring music - he subsequently asked them to celebrate more respectfully.

No-one except those who were involved can vouch for whether that is indeed what started the melee, but it's clear the Red Devils boss was unhappy.

In Tuesday's press conference, this was put to Pep Guardiola and while he wouldn't discuss whether his opposite number had entered the City dressing room, he did offer his own take on his players' antics.

Pep responds

"Some players go to celebrate with the fans like normal. I am the guy who encouraged them to celebrate between each other. And that is what we did.

"And after what happened, hopefully it cannot happen again."

When the question was put to him whether the celebrations were too much, he added:

"Definitely not, it was the same after the Southampton game. We were happy.

“We won a derby, against United, at that moment the best rival we have to win it. What do people expect we don’t celebrate?

“No, we celebrate, but I think, when United win games, they celebrate. When Arsenal beat United, they celebrate... We try to do it in the locker room. That is what we try to do, and we did.

“It was correct. We jumped because we were happy. Of course, in that moment, we want to celebrate.”

So, Guardiola is absolutely not backtracking.

Jose hits back

Mourinho's press conference was scheduled at the same time, which in theory meant he wouldn't be able to respond. However, the Portuguese did have a retort for his City counterpart.

"I’m not here to comment his words, the only thing I can say is for me it was a question of diversity in behaviour, in education, nothing more than that," he said.

The gloves are well and truly off.

Do you think City's behaviour went too far? Have your say in the comments.