Watch Conor McGregor suffer horrific broken leg in first round with career in doubt as he loses to Poirier at UFC 264

CONOR McGREGOR suffered a crushing defeat to Dustin Poirier after breaking his leg in the first round.

The Irishman was beaten by rival Poirier in their third bout at UFC 264 headline in Las Vegas on Saturday night.

But the fight ended in chaos when McGregor broke his leg- leaving the referee no choice but to stop the bout.

McGregor suffered a broken tibia in his lower left leg and was taken out of T-Mobile Arena on a stretcher.

But the former two-weight champion insisted the rivalry with Poirier is 'not over' as the pair were STILL trading words post-fight.

McGregor, 32, said: "I was boxing the bleeding head off him, kicking the bleeding leg off him.

"Usual s***e, dive to close the distance. This is not over. I have to take this outside with him, it's all outside."

UFC legend Jon Jones was among those to send McGregor well wishes, but casted doubt over his fighting future.

Jones, 33, tweeted: "Man, I wonder if he will ever fight again after this.. heal up champ, this is terrible."

The lightweight rivals came into the fight tied at one apiece, with McGregor winning the first in 2014 but Poirier avenging defeat in January.

They wasted no time in getting back down to business, with McGregor opening up with some heavy leg kicks.

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McGregor was also switching stances as looked to control the distance on the outside.

But Poirier then stunned The Notorious with a combination as the pace began to really pick up.

The American mixed up the levels to take McGregor down, who reacted by attempting a guillotine choke.

But after failing to lock in the hold, Poirier began to reign down with some brutal ground and pound.

When the pair finally stood up, McGregor's attempted kick backfired as he came down on his shin, which gruesomely gave way, forcing him to fall down.

Poirier reacted by again looking to finish McGregor on the floor before the bell sounded.

But it became clear he suffered a fight-ending injury as the doctor waved off the contest, declaring him the loser by technical knockout.

Before the fight, McGregor boasted how he had Poirier's wife, Jolie, messaging him on Instagram.

And as the bad blood spilled over, again he looked to goad Poirier.

McGregor said: Your wife is in my DM's. Hey baby, hit me back up and I'll chat to you later on.

"We'll be having an afterparty at the Wynn nightclub baby."

McGregor - who promised Poirier would be leaving on a stretcher - was the one assisted out of the T-Mobile Arena.

But he left adamant on keeping the chapter open, meaning a FOURTH fight between himself and Poirier cannot be ruled out if he makes a recovery.