Ali Abdelaziz made the powerful comments following his client’s successful title defence.
Speaking at a press conference, he said: “There was never two Kings from the beginning, only one King.
“I want to congratulate my brother Khabib Nurmagomedov, the undisputed, undefeated pound-for-pound King.”
In the aftermath of the fight, Nurmagomedov leapt out of the cage and appeared to assault one of McGregor’s team.
This triggered an all-out brawl between the two parties, which had to be broken up by security staff.
Three of Nurmagomedov’s team were arrested, but were later released after McGregor decided not to press charges.
Mr Abdelaziz apologised for these scenes whilst appearing to make another dig at McGregor.
He said: “The fans got an amazing fight and a great show.
“I want to apologise to the Nevada Athletic Commission, the Governor of Nevada and I want to thank the Las Vegas police department and security for doing such an unbelievable job.
“Now everyone understands who’s the amateur here.”
There was considerable tension between McGregor and Nurmagomedov before the fight stemming from a number of incidents.
In April, McGregor threw a metal trolly through the window of Nurmagomedov’s team bus during the UFC 223 media day in Brooklyn.
In July, he was found guilty of disorderly conduct after a plea deal with the Brooklyn District Attorney.
He went on to insult Nurmagomedov’s family and appeared to mock his Islamic faith by offering him whisky.
McGregor also launched a racially charged rant at Mr Abdelaziz who he described as a “f**king snitch, terrorist and rat”.
McGregor has already raised the prospect of a rematch tweeting: “Good knock. Looking forward to the rematch.”