The MMA world has reacted with a mixture of shock and admiration after Khabib Nurmagomedov announced he was retiring after submitting Justin Gaethje to retain his lightweight title at UFC 254 in Abu Dhabi.
Khabib defeated interim champion Gaethje in the second round via triangle-choke submission on Fight Island to extend his unblemished professional record to 29 fights, before announcing in the cage that it would be his last bout.
Visibly emotional, Khabib spoke of the toll of losing his father and trainer Abdulmanap to coronavirus complications in July, revealing that he had promised his mother that this would be his last contest.
Immediately after hearing, the news the MMA world reacted to the Dagestani's dominant performance against Gaethje as well as the realization that they would never see him in action in the octagon again.
Former two-weight UFC champion Daniel Cormier - Khabib's friend and teammate at the American Kickboxing Academy, and who was calling the action cageside for the UFC - hailed him as "the greatest champion in UFC history."
UFC commentator and podcast megastar Joe Rogan likewise stated that Khabib was the greatest ever to do it.
UFC light heavyweight champion Jan Blachowicz also tweeted his admiration, as did fellow UFC stars such as Kelvin Gastelum and Cody Garbrandt.
Current welterweight ruler Kamaru Usman also offered praise, while Australian featherweight champion Alex Volkanovski called Khabib the world's "pound for pound number 1."
Former light heavyweight champion Jon Jones - a man rated by many as among the contenders for GOAT status - also congratulated Khabib.
The UFC's own Twitter account simply stated that 'The Eagle' had left "a legacy like no other."
Former UFC fighter-turned-pundit Dan Hardy called Khabib's performance against Gaethje - whom many had tipped as his most dangerous opponent to date - "one of the greatest performances" he had seen in the octagon.
MMA fans also poured onto social media to praise Khabib, with one writing that the Dagestani grappling phenom had "always taken the sport and the organization on his own terms."
Others said Khabib "would have done his father proud" with his performance in Abu Dhabi.