Khabib was set to defend his title against Tony Ferguson on 18 April 2020 at UFC 249, marking the fifth time the fight had been scheduled. Both fighters were on 12-fight win streaks, but COVID-19 travel restrictions left Khabib unable to leave Russia, forcing him off the card. Ferguson instead faced Justin Gaethje for the interim lightweight title, with Gaethje winning via fifth-round TKO to secure a shot at Khabib.
Unification Bout
On 24 October 2020, Khabib faced Gaethje in a unification bout at UFC 254. It was an emotional fight for Khabib, his first without the guidance of his father, who had passed away earlier in the year. Khabib secured victory with a second-round triangle choke, unifying the titles. Overcome with emotion, he broke down in tears, comforted by Gaethje in a heartfelt display of sportsmanship.
In his post-fight interview, Khabib announced his retirement, citing a promise to his mother to stop fighting without his father by his side.