The biggest surprise about events in Las Vegas on Saturday night into Sunday morning was that there was surprise it had come to this.

The irony is that the fight itself between Conor McGregor and Khabib Nurmagomedov was everything that MMA supporters said it could be. There was tension, remarkable physical determination, skill and a real mix of martial arts.

That McGregor was clearly second best throughout will not have raised the excitement of his legion of Irish fans but it could have gone down as a genuine step forward for the sport, and perhaps been a part of his legacy.

Then all hell broke loose. Nurmagomedov broke away from security and leapt the fence to launch into the area where McGregor’s coaches were sitting. There was a wild melee of private and city police and while attention swung to that three members of the Nurmagomedov team attacked McGregor. They were bigger, they were striking a man who had just been through the wringer and it was a sad and sorry episode.

The Irish and Russian fans in the crowd thought little of right and wrong, apart from in relation to their own man, and the anger spilt out onto the streets.

It has happened before in many sports that anger gets the better of young men and things are done outside the realm of what sport is intended for.

Sometimes described as war without guns, the unwritten rule is that no matter what happens in the game you shake hands and walk away.

The build-up to this fight though has had little to do with sport and everything towards glorifying true violence as opposed to the sporting variety.

McGregor’s attack on a Nurmagomedov team bus in New York was an act of assault. His words of venom towards his opponent another layer of what supporters would call promotion but which stepped way beyond that and should have been called out and stopped.

If it cost 1,000 or 1,000,000 pay per views, so what. It was all wrong on many levels and the direct cause of what happened on Saturday.

Even if the two combatants come back and somehow decide that a rematch is in their own best (financial) interests. There should be a line drawn.

What if somebody had been injured or killed on Saturday night. What if anger, stoked by the UFC publicity machine and fuelled by lager in the desert of Nevada had led to a punch being thrown or a knife drawn and a life being lost.

This is a sport which has edge, it has spark, it has skill, regardless of your appetite for blood on the canvas, and it has a place somewhere in the sporting pantheon of the 21st Century.

But if it persists in using hatred as a playbill, then it loses the right to that place.

Conor McGregor is nobody’s fool and his coach and mentor John Kavanagh is a thoughtful and intelligent man. They avoided the press conference after and while a single tweet that he was looking for a rematch would suggest he was ignoring both his own defeat and the loss of dignity and danger that followed; they both need to think long and hard about a next step.

Three years ago there was talk of a bout in Croke Park before 80,000 fans. It looked like a pipedream then. It looks now as though we must have been mad to have given it airtime at all.