Conor McGregor
McGregor was rocked in the second before Diaz locked in his chokehold. Getty

Nate Diaz has shocked the UFC world with a submission victory over Conor McGregor at UFC 196.

Diaz was a late replacement for Rafael dos Anjos just 11 days ago but sealed his huge win via a rear naked choke in the second round, denying McGregor his eighth consecutive UFC win at the MGM Grand in Las Vegas.

It was the Dublin-born fighter's first defeat in UFC and just his third in mixed martial arts.

A series out solid lefts opened up Diaz in the first round but the 30-year-old weathered the early storm, escaping a takedown in the closing stages of the opening round. Diaz continued to bleed from the cut above his right eye but it didn't prevent him from staging a fight back.

Half way though a wild second round, McGregor, 27, was visibly rocked after taking two solids rights, leaving him more vulnerable than he had ever looked before in a UFC ring. He was left in serious trouble when Diaz mounted him to land more, dominating his opponent on the ground who was too dazed to defend himself. Out of desperation, the Irishman attempted a takedown of his own, but saw it reversed and was unable to escape as Diaz sealed the submission victory, the 12th of his career.

Featherweight champion McGregor stepped up two weight classes to take the Diaz fight but made no excuses for himself after the defeat.

"I took the chance," McGregor said. "I thought I took first round, I was inefficient with my energy. I respect Nate, he took the punch. These things happen in MMA. I took a chance and it didn't work out."