McGregor had to leave the T-Mobile Arena on a stretcher and he could be out of action for up to a year.
However, the 'Notorious' took to Instagram and told fans: "You need people like me" in a cryptic message.
Official UFC scorecards had Poirier in the lead but it was still an anti-climactic end to the evening's main event.
McGregor aimed a punch at the 'Diamond' but fell back onto his leg as it buckled beneath him right as the round ended.
It comes after a week of post-fight build-up in which 'nasty' McGregor had returned and attempted to get in Poirier's head.
He even told him he'd be going out on a stretcher - before doing so himself.
"Dustin's going out in a stretcher," McGregor told Ariel Helwani on BT Sport.
"That's my prediction. He's going out of this fight in a stretcher.
"I'm ready for it all," McGregor said when asked about how long the fight would go.
"I'm not jumping the gun... But he's going out in a stretcher... Early."
Longtime rival Khabib Nurmagomedov watched the fight and was delighted to see Poirier come out on top.
He tweeted: "Good always defeats evil. Very happy for Dustin Poirier. I hope you will get the belt end of the year."
Good always defeats evil.- khabib nurmagomedov (@TeamKhabib) July 11, 2021
Very happy for @DustinPoirier I hope you will get the belt end of the year
He also retweeted a comment from Daniel Cormier in which he referenced McGregor's trash talk.
UFC legend Cormier said: "Crazy to think that at the end of the weigh in Conor said he would be taken out on a stretcher. And now Conor gets taken out on a stretcher. Man this game we play is so crazy!!!! Hats off to the Diamond of Lafayette!!"
Next up for Poirier is likely lightweight champion Charles Oliveira.
UFC president Dana White has confirmed McGregor vs Poirier IV is likely once McGregor has recovered.
Featured Image Credit: BT Sport & Conor McGregor/Instagram
Chosen for YouChosen for You
Most Read StoriesMost Read