"F*** your whole team - little crack head arses," McGregor fired back.
Diaz and his crew circled through the David Copperfield Theater at the MGM Grand before reaching the stairs where they were just a few feet away from McGregor's team, which included several coaches including Owen Roddy and his grappling partner Dillon Danis.
The situation quickly turned volatile as McGregor and Diaz continued to taunt each other back and forth with threats being lobbed each way.
"Shut your f***ing mouth, you'll do nothing," McGregor shouted. "Not one of you's will do nothing! Get the f*** out of here!"
As if the verbal exchanges weren't enough, Diaz then launched a water bottle at McGregor's team and that's when the press conference turned into a chaotic scene as the two teams started moving towards each other and it looked like a full blown brawl was about to take place.
Security rushed in to keep the teams separated, but McGregor - who was still on stage - started picking up cans and bottles placed on the table for the athletes in attendance and firing back at Diaz and his camp on the stairs.
UFC president Dana White tried to stop McGregor from launching the bottles and cans at Diaz's team, but by that point things had already gotten very ugly.
"That's a wrap, get him out of here," White said to the UFC staff trying to pull McGregor away from the stage.
McGregor was eventually dragged backstage while Diaz and his team made their exit after the near melee erupted.
Over the course of the build up to the fight, McGregor and Diaz have both been rather subdued in their attacks towards each other but finally sitting in the same proximity to each other quickly brought back the ill will they clearly share.
The two fighters never got to the customary pre-fight stare down thanks to the near brawl, but McGregor and Diaz will face off at the weigh-ins on Saturday NZ time where security will likely be on hand to ensure UFC 202 doesn't kick off 24 hours early.
