Charles Oliveira retained his UFC lightweight title as he staved off the challenge of former interim champion Dustin Poirier via submission at UFC 269 in Nevada on Saturday.

Poirier had come into the fight looking to claim Oliveira's title as champion following back-to-back wins over Conor McGregor but was beaten in the third round by rear-naked choke.

The American had started well, unsettling Oliveira and dropping him to the ground with a first-round left hook. Oliveira repelled the barrage and responded with a left hook of his own late in the first.

Oliveira, known as one of the greatest submission artists in UFC history, floored Poirier in the second round, landing hard elbows.

In the third, Oliveira put Poirier into a clinch against the cage, taking his opponent's back and finding the choke that would lead to the submission.

“I’m the world champion. I’m the man. They talk, I do it," Oliveira (32-8, 1 NC) said after the fight after his 10th win in a row. "I'm gonna walk forward. They can hit me a lot." Oliveira has the most finishes (18) and the most submission wins (15) in UFC history.

Pena pulls off massive shock over Nunes

Julianna Pena produced a major upset as she submitted double champion Amanda Nunes in the second round of their bantamweight title fight.

Pena (11-4) stunned Nunes, who had not lost since 2014, despite the Brazilian appearing well in control early, before the American started landing strikes (79-46 according to UFC stats).

The submission came at 3:26 in the second round as Pena grounded Nunes before locked in a rear-naked choke.

"Don't ever doubt me again," Pena said after the fight. "She tapped and I asked the commission, 'Is it over?' He said, 'Yes, you won.' It didn't [seem real]. It feels crazy. But I expected to win. The world is my oyster. You have the ability to do anything you want in this life."