What is the fastest knockout in a UFC title fight?

The fastest knockout in a UFC title fight took 13 seconds. Conor McGregor stopped José Aldo at UFC 194 on December 12, 2015, winning the undisputed featherweight championship.

Aldo entered the bout as the reigning champion and had not lost a professional fight since 2005. After a brief exchange, Aldo threw a wide left hook; McGregor slipped the punch and countered with a perfectly timed left hand that dropped him almost immediately. Two follow-up hammerfists prompted referee John McCarthy to stop the contest.

The result ended Aldo’s long featherweight reign and completed McGregor’s unification of the division after he had previously won the interim belt from Chad Mendes. The official stoppage time was 13 seconds of the first round.

This record is often confused with the fastest UFC knockout overall. Jorge Masvidal’s five-second flying-knee knockout of Ben Askren at UFC 239 is faster, but it was not a title fight. In championship history, McGregor–Aldo remains the standard.