UFC 279: Diaz vs. Ferguson was a mixed martial arts event produced by the Ultimate Fighting Championship that took place on September 10, 2022, at the T-Mobile Arena in Paradise, Nevada, part of the Las Vegas Metropolitan Area, United States. A welterweight bout between Khamzat Chimaev and former lightweight title challenger (also The Ultimate Fighter 5 lightweight winner) Nate Diaz was originally expected to headline the event. However at the weigh-ins, Chimaev weighed in at 178.5 pounds, 7.5 pounds over the welterweight non-title limit and the bout was cancelled. As a result, the organization opted to shuffle a trio of fights: a new main event featuring Diaz against former interim UFC Lightweight Champion (also The Ultimate Fighter: Team Lesnar vs. Team dos Santos welterweight winner) Tony Ferguson, who was originally scheduled to face Li Jingliang in a welterweight bout, was then set.