A lightweight trilogy between former interim UFC Lightweight ChampionDustin Poirier and former UFC Featherweight and Lightweight Champion Conor McGregor headlined the event.[6] Their first fight was a featherweight bout that happened in September 2014 at UFC 178, where McGregor won by first-round technical knockout.[7] They then ascended to lightweight for an eventual rematch in January 2021 at UFC 257, where Poirier prevailed via second-round knockout.[8] During fight week, it was revealed that former lightweight champion Rafael dos Anjos was selected by the organization to serve as a potential replacement in case of need.[9]
A welterweight bout between Sean Brady and former interim UFC Lightweight Championship challenger Kevin Lee was expected to take place at the event.[12] However, Lee withdrew due to injury and the bout was removed from the event.[13]
A bantamweight bout between Sean O'Malley and Louis Smolka was expected to take place at the event.[14] However on June 29, Smolka withdrew due to an undisclosed injury.[15] He was replaced by promotional newcomer Kris Moutinho.[16]
At the weigh-ins, Irene Aldana weighed in at 139.5 pounds, three and a half pounds over the bantamweight non-title fight limit. Her bout proceeded at catchweight and she was fined 30% of her purse, which went to her opponent Yana Kunitskaya.[17]
On July 9, it was announced that the UFC would be increasing bonuses (Fight of the Night and Performance of the Night) from $50,000 to $75,000 for this event.[18]
A middleweight bout between Alen Amedovski and Hu Yaozong was scheduled to be the first preliminary bout of the event.[19] However, it was cancelled just hours before taking place due to COVID-19 protocol issues in Amedovski's camp.[20]