Despite its natural brutality as a sport, one of the most important things when it comes to UFC is the wellbeing of the fighters inside the cage.
They may spend the entirety of the fight beating the living daylights out of each other, but there is still an element of safety overlooking the bout, and that element of safety is usually the referee.
Standing inside the cage with the fighters, the ref has the best view of the fight and they should know when the bout is getting out of hand or when it needs to be waved off.
If one fighter is being brutally punished by the other and showing no sign of defence or fight back, it's the referee's duty to wave it off and protect the fighter in danger.
However, that didn't happen at UFC 267 yesterday in Abu Dhabi.
During the welterweight bout between Zaleski dos Santos and Benoit Saint-Denis, which took place on the prelims, fight official Vyacheslav Kiselev failed to stop the fight, despite the fact it was turning into a one-sided assault.
Dos Santos was clearly on top of the fight once it reached the second round, and Saint-Denis simply couldn't defend himself or offer any attack back. It was very clear that the fight should've been waved on, but instead, it went the full distance.
Of course, Brazilian Dos Santos was eventually crowned the winner via unanimous decision, but fans and even the commentators were left confused by the lack of action taken by Kiselev.
Due to his performance, or lack of it in this case, the match official was pulled from his duties for the rest of the night.
UFC has pulled referee Vyacheslav Kiselev from his other #UFC267 assignments due to his performance during the Zaleski dos Santos-Saint Denis fight. pic.twitter.com/lt04N8b6ax
Speaking about the performance of the referee, commentator Jon Anik addressed the situation and informed the fans what had happened by saying: "I can tell you that Vyacheslav Kiselev has been removed from his next assignment.
"He will not be refereeing any more tonight after what we all witnessed in the Saint-Denis/Zaleski dos Santos fight."
He wasn't the only one to weigh in, however, as former champion Daniel Cormier expressed his concern over the ref's performance.
He said: "Honestly the worst performance I have seen from a referee in my life. Honestly a hard job but man. Unreal.
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"It makes you respect the good ones like Jason Herzog, John McCarthy and Herb Dean and many more. I hated watching that I hope Benoit is heading to hospital right now."
It's safe to say we may not see Vyacheslav Kiselev officiate a UFC fight anytime soon.