They're keeping their spirits up ahead of the big night anyway.
The UFC's official Instagram posted a video in the early hours of this morning, which shows some enthusiastic Conor McGregor fans dancing... in the middle of a Las Vegas road.
The video went live yesterday evening local time, and was most likely filmed after the weigh-in for tonight's UFC 194 main event - the featherweight unification bout between McGregor and Jose Aldo.
The weigh-in was preceded by a Holly Holm Q&A, which featured lots of enthusiastic Irish fans - some of whom serenaded the new UFC women's bantamweight champion.
Then the party appeared to spill out onto the streets with chants of 'lets go f**king mental'.
Then they stormed a Las Vegas road and decided to stay there and have a party.
https://www.instagram.com/p/_LY8yeJJfW/?taken-by=ufc
And proceeded to rip the p*ss out of one poor police officer with a whistle trying to stem the Irish tide of mayhem and merriment.
