UFC star Conor McGregor tweeted a message of respect to Khabib Nurmagomedov on Saturday after Khabib defeated Justin Gaethje at UFC 254 and subsequently announced his retirement.

McGregor congratulated Khabib on his win and retirement and also offered condolences regarding the death of Khabib's father:

Nurmagomedov beat Gaethje by second-round submission to retain the UFC lightweight title and improve his career record to 29-0. After the bout, Khabib retired on the basis that he no longer wanted to fight without his father around:

Khabib's father, Abdulmanap Nurmagomedov, died at the age of 57 in July due to complications related to COVID-19.

Abdulmanap was an expert in wrestling, judo and sambo, and he served as Khabib's trainer for many years, as well as the combat sambo national team coach in his native Dagestan.

McGregor and Khabib fought back at UFC 229 in 2018. Nurmagomedov won that bout by fourth-round submission, but chaos broke out after the fight, as members of both fighters' teams brawled inside and outside the Octagon.

Since losing to Khabib at UFC 229, McGregor has pushed for a rematch on several occasions. McGregor's only UFC bout since that loss was a win over Donald "Cowboy" Cerrone at UFC 246 in January, and he announced his retirement on Twitter in June.

McGregor tweeted last week that he had agreed to come out of retirement and fight Dustin Poirier in January 2021, however:

It was widely assumed that the winner of that fight would be in line for a title match with the winner of Khabib vs. Gaethje, but that is no longer the case with Nurmagomedov opting to retire.

Now, McGregor, Poirier, Gaethje and Tony Ferguson all figure to be in the UFC lightweight title mix, and it stands to reason that UFC President Dana White could look to set up a de facto tournament involving them to determine the new champ.

McGregor vs. Khabib II undoubtedly would have been a massive box-office draw for UFC, but McGregor's tweet Saturday suggests that he is content to respect Nurmagomedov's decision and drop any attempts to convince him to fight one more time.