Dustin Poirier Says Conor McGregor Beef Will Never Be Over

Dustin Poirier's fighting for the lightweight title on Saturday ... but the UFC star openly admits the drama with Conor McGregor isn't over -- and never will be.

TMZ Sports talked to a very focused Poirier -- just days before his UFC 269 main event title fight with Charles Oliveira -- and we asked if the beef with Conor was finally squashed.

"Nah, the chapter will never be closed," Dustin says, clearly not loving the McGregor topic.

It's not a surprising comment ... as Conor said some very personal things about Dustin and his wife.

Of course, 33-year-old Conor and 32-year-old Dustin have already fought 3 times. The first scrap was way back in 2014 ... when McGregor won by TKO.

However, DP beat CM twice this year ... in January and July, when The Notorious gruesomely snapped his leg.

But, a 4th fight is anything but guaranteed ... 'cause Poirier -- who has won 7 of his last 8 -- is fighting for a title, and McGregor's still nursing the busted leg.

"I don't know [about a 4th fight], we'll see what happens. [Conor and I are] in 2 completely different spots if I get my hand on this belt."