Who recorded the fastest knockout in UFC history?

Jorge Masvidal recorded the fastest knockout in UFC history.

Masvidal stopped Ben Askren with a flying knee at five seconds of the opening round in their welterweight bout at UFC 239 on July 6, 2019. The finish came immediately after the referee started the fight, making it the fastest knockout officially recorded in UFC history.

Askren attempted to shoot for a takedown, and Masvidal launched forward with a jumping knee that landed cleanly. Masvidal then followed with strikes before referee Herb Dean stopped the contest. The official result was a knockout at 0:05.

The record is sometimes confused with the fastest knockout in all major mixed martial arts, where records can vary depending on the promotion and how the time is documented. It is also distinct from the fastest UFC submission or the fastest finish achieved by a particular fighter. Masvidal’s five-second finish remains one of the most recognizable moments in UFC history.