Conor McGregor

Conor McGregor became the first simultaneous two-division UFC champion in 2016 by knocking out Eddie Alvarez in the second round at UFC 205. His 13-second KO of José Aldo at UFC 194 remains the fastest finish in UFC title-fight history, a feat that made him the biggest pay-per-view draw ever with 4.4 million buys for his 2017 bout with Floyd Mayweather. McGregor's 17-4 record in the UFC includes wins over four former champions, but his career is distinguished by commercial impact: his 2016 fight with Nate Diaz generated $90 million in gate revenue, outperforming the average UFC event by 700%.