'Crazier than my fight riot' - even Tyson shocked by post-fight brawl
Conor McGregor's UFC return did not go to plan as Khabib Nurmagomedov delivered a career-best display to win by submission - but that soon became an afterthought amid chaotic post-fight scenes in Las Vegas.
An ugly brawl between the camps provoked a strong reaction on social media - much more so than the actual outcome of the fight.
Former heavyweight boxer Mike Tyson set the tone when claimed the brawl outdid the night he bit off part of Evander Holyfield's ear in 1997.
"Unimaginable never thought it would go down like this," Tyson wrote. "Crazier than my fight riot."
Former UFC lightweight champion of the world Rafael dos Anjos was less than impressed by Nurmagomedov and his team, calling their actions "unacceptable".
"You can't jump the fence and punch the fighter," he said.
Many pointed to McGregor's attack on Nurmagomedov's on a bus in April - footage of which was used in promoting this fight - as justification for Nurmagomedov's actions, but a number of MMA fighters disagreed.
Megan Anderson claimed "one evil doesn't make another ok" and said Nurmagomedov should have risen above what had happened.
"As a champion, you set a higher standard," she wrote. "You don't stoop to that level. This is not the actions of a champion."
Corey Anderson felt the incident would be used to paint McGregor as "the victim" while Daniel Cormier said it showed that "some things aren't for fight promotion".
British boxer Tony Bellew chimed in too to condemn the post-fight attack on McGregor.
"Connor (sic) lost the fight fair and square yes.. Not a chance in the world he deserves to be attacked by 2 men!" he wrote, adding: "It's a disgrace! People bringing up the bus incident? No comparison!"
British MMA fighter John Maguire suggested there might be a more cynical motive behind the drama.
"Don't worry people it will all be forgotten about in a couple of weeks and then there will be a even bigger build-up for a rematch," he wrote.
Others wondered if McGregor would return to a UFC ring again.
Olympic boxer Tony Jeffries wrote: "Gutted for Connor (sic), the most entertaining man in sport... I hope this isn't the end."
But he could take reassurance from the message from McGregor's own coach, which suggested he plans to be back.
"Another historical night," John Kavanagh wrote. "Amazing atmosphere, technical fight with excitement all the way thru.
"All that makes MMA a great sport. Shame about the ending. On to the next one."