The Dubliner made his professional boxing debut against five-weight champ Mayweather at the T-Mobile Arena, moving across from mixed martial arts for a twelve round light middleweight contest.
The fight was shown on Showtime pay-per-view and was priced at $99.95
Following a good start, a fatigued McGregor would unravel and was eventually stopped standing in the tenth round.
A mega event, the cross codes clash has seemingly smashed all pay-per-view records.
UFC President Dana White, who was heavily involved in the making of the fight, claimed on his Tuesday Night Contender series that the fight pulled in a whopping 6,500,000 buys.
Official confirmation of the figure is expected soon.
The previous American record stood at 4,600,000 buys, set by Mayweather’s fight against Manny Pacquiao in 2015.
Numbers for the UK and Ireland, where the fight was aired on Sky Box Office, are yet to be confirmed – however Matchroom Promotions boss Eddie Hearn has noted before the fight that they were huge and potentially record breaking.
The prices on this side of the Atlantic were £19.95/€24.95, rising by £5/€5 on the day of the fight.
The previous record in the UK and Ireland was for Anthony Joshua v Wladimir Klitschko in April which, while unconfirmed exactly, were over 1,500,000.