"There is no holds barred with the trash talk, right. But murder is something you don't clown around with and there is no coming back from that."
McGregor was forced to retire after a nasty ankle injury near the end of the first round, an injury which Poirier says he sustained with a check kick early on in the fight.
After a good start by the Irishman, Poirier took McGregor down and dominated the latter half of the first round before McGregor went over on his left ankle attempting a kick.
Following a tense build up to this trilogy fight, Poirier showed his frustration with McGregor's trash talk afterwards.
"He fractured it with one of his checks early on, then it broke on the punch for sure," said Poirier afterwards.
"It was probably cracked and then on the twist of the punch it finished (him off)."
It was put to Poirier that there was a lot of tension between the pair in the lead up to the fight despite the last clash being a friendly affair, and the victor did not mince his words.
"There is no holds barred with the trash talk, right. But murder is something you don't clown around with and there is no coming back from that.
"This guy was telling me he was going to murder me and all kinds of stuff and saying he was going to kill me and I was going to leave here in a coffin. You don't talk to people like that. I hope this man gets home safely to his beautiful family."
On the fight, Poirier added: "He did hit me with a good cross like the last fight. I was a little bit buzzed but my legs were still there. The take down was easy. He was putting his fingers in his gloves and pulling me down to try the up kicks. This guy is a dirtbag man."
A raging McGregor was keen to make his point as he lay motionless on the canvas.
"This is not over. If I have to take this outside, I'll take it outside. I don't give a b****x," said the Irishman.