UFC 91 was the first UFC pay-per-view event reported to sell more than one million buys.
Held on November 15, 2008, in Las Vegas, UFC 91 was headlined by heavyweight champion Randy Couture defending his title against Brock Lesnar. Lesnar won by unanimous decision and became the UFC heavyweight champion.
The event’s reported success marked a major commercial milestone for the promotion. Lesnar’s professional-wrestling fame brought a large audience to the UFC, while Couture’s status as a former champion made the matchup especially prominent.
UFC 100 is often remembered as the promotion’s biggest early pay-per-view success, but it was not the first to pass the one-million-buy mark. UFC 91 reached that milestone before UFC 100, which followed in 2009 with another Lesnar headline bout.