'Well it is Conor McGregor’s final roll of the dice, if he loses this one it’s curtains, isn’t it?'
McGregor beat the American back in 2014 but Poirier handed the Crumlin man a shock second round knockout defeat when they met in January.
With the series now tied at 1-1 McGregor is in desperate need of a win in the trilogy bout to reignite his career.
The Notorious steps into the Octagon next month to face the Diamond for the second time this year but if he loses, it will be “curtains” for him, according to Tyson.
He told former UFC star Michael Bisping: "Well it is Conor McGregor’s final roll of the dice, if he loses this one it’s curtains, isn’t it?
"I think he wins this fight, and I think he wins this fight in style as well.
"With Conor you never know what he’s been doing, you never know what he’s been up to in training camps and all that.
"From what I hear, he lives like a rockstar while he like a week away from his fight. You can’t do that.
"When I’m in training camp I’m 100 per cent dedicated to the fight, I don’t do anything. I go to bed early, I get up earlier, I don’t drink anything but water.
"I dedicate 100 percent to the job at hand. If I was going out and getting smashed the night before a fight, then I’m asking to lose."
However, as he returns to fight on US soil in front of a packed Las Vegas crowd, McGregor appears determined to get revenge on that defeat in January.
He said: "I lost that night, it stung. And I must get that back.
"Now I have an opportunity to get my revenge."
And on Instagram he posted a photo of him landing a shovel hook on Poirier, with the words: "25 days I finish the job."
The former two-weight champion has moved his training camp from Dubai to California as he puts the finishing touches on his preparations.
McGregor has been pictured cycling to training in recent days, with other snaps showing him bench pressing over 50kg.
The Dubliner says he feels very confident ahead of the UFC 264 contest, telling Fox Sports: "All the marbles are on the line. I'm here training very, very hard. I'm about to go for my second session of the day. I'm in great condition already.
"I beat him in the original bout [in 2014]. I lost in the rematch. And then we've got trilogy, I've got a few little adjustments to make."