Khabib Nurmagomedov made his latest case to being called the greatest mixed martial artist ever on Saturday. Then he stunned the world.

Nurmagomedov defended his UFC lightweight championship in the main event at UFC 254, using his world class ground game to take down challenger Justin Gaethje and finish him with a triangle choke at 1 minute, 34 seconds of Round 2.

But during his post-fight interview after moving to 29-0, Nurmagomedov announced his retirement, saying he didn't want to fight anymore without his father in his corner. Abdulmanap Nurmagomedov died in July from heart complications made worse by the coronavirus.

Nurmagomedov's fellow UFC fighters took to social media immediately after Saturday's main event to praise him, with several calling him the best fighter, pound for pound, in the world.

Good performance @TeamKhabib.
I will carry on.
Respect and condolences on your father again also. To you and family.
Yours sincerely, The McGregors.

— Conor McGregor (@TheNotoriousMMA) October 24, 2020

Until I take that heavily crown, I grant you the spot. ?? Enjoy Champ

— BONY (@JonnyBones) October 24, 2020

Congratulations to the greatest champion in @ufc history. What a career, we are forever grateful for the time we got to spend with you my brother. 29-0 undefeated and undisputed. #weareaka #eaglesmma #fathersplan #heissoproud ⁦@TeamKhabib⁩ pic.twitter.com/uXjiT34JuV

— Daniel Cormier (@dc_mma) October 24, 2020

Congratulations to my brother ???? @TeamKhabib and keep your head up my brother @Justin_Gaethje #UFC254

— KAMARU USMAN (@USMAN84kg) October 24, 2020

Wow what a legend!!! @ufc @TeamKhabib

— "Young Superstar" (@Benaskren) October 24, 2020

The best to ever do it @TeamKhabib

— Cody Garbrandt (@Cody_Nolove) October 24, 2020

I'm 100% behind giving @TeamKhabib the #1 P4P ranking! Absolutely earned! Congrats on an AMAZING career. You are an inspiration. Much love. ???? #UFC254

— Stephen Thompson (@WonderboyMMA) October 24, 2020

He's definitely #1 pound for pound!! Congratulations on a great career #UFC254

— Alex Volkanovski (@alexvolkanovski) October 24, 2020

Outstanding champion, incredible career and amazing achievements. Congrats and all the best outside the Octagon @TeamKhabib! https://t.co/Ze2CZrcSqT

— Jan Blachowicz (@JanBlachowicz) October 24, 2020

Wow! Much respect to you ???. Good luck, God bless @TeamKhabib

— Dominick Reyes (@DomReyes) October 24, 2020

Getting emotional watching this. Wow. Khabib respecting his mother and following through with his word. What a man. Deffo a top 5 goat of MMA. Happy retirement. pic.twitter.com/dkqOlcS3OR

— D (@darrentill2) October 24, 2020

Wow incredible story and career @TeamKhabib . You are something special my man ??????

— Eddie Alvarez (@Ealvarezfight) October 24, 2020

Wow. #Khabib is simply unbeatable. Congrats to one of the most dominant athletes in the history of any sport. #UFC254

— Rob McElhenney (@RMcElhenney) October 24, 2020

The way Khabib is able to drain energy from his opponents it's unique.
I think he deserve the #1 p4p spot.#UFC254 #khabib

— Marvin Vettori (@MarvinVettori) October 24, 2020

One of the most humble guys I know and most sportive @TeamKhabib Earned his spot in greatness. Made his country and brothers proud and most of all his father. God Bless you brother. Wish you the best in what life has to offer you more. #UFC254 #khabibnurmagomedov #khabib

— Gökhan Saki (@gokhantherebel) October 24, 2020