Leon Edwards lost his UFC welterweight title after he was shocked by Belal Muhammad at UFC 304 in Manchester.
Muhammad out-grappled Edwards throughout the fight and a was awarded a unanimous decision.
“Not surprising, my body just felt tired from round one,” said Edwards. “All week I've felt tired. Congratulations to Belal, we will be back.”
The fight took place just after 5:30 BST to cater to an American audience.
Jamaica-born, Birmingham-raised Edwards was crowned 170lb champion with a last-round knockout of Kamaru Usman in 2022 and he outpointed the Nigerian-American the following year in his first defence.
Edwards claimed a unanimous decision victory over Colby Covington in a grudge bout in his most recent outing in December to extend his unbeaten streak in mixed martial arts to 13 fights.
That run came to an end in Manchester as Muhammad outlasted Edwards over five arduous rounds, with judges scoring the contest 48-47, 48-47, 49-46 in favour of the American.
The bout was a rematch from March 2021, when a no-contest was called after Edwards' accidental eye-poke early in the second round rendered Muhammad unable to continue.
Elsewhere on the card, Salford's Tom Aspinall called out Jon Jones after he avenged a previous loss to Curtis Blaydes, retaining his interim heavyweight title with a knockout victory in the first round.
And Liverpool's Paddy Pimblett clinched a spot in the top-15 lightweight rankings with a first-round submission victory over Bobby Green.
