Julianna Peña pulled off what has been described as the 'biggest upset in UFC history' on Saturday night in Las Vegas.

Against all odds, The Venezuelan Vixen submitted Amanda Nunes at UFC 269 to clinch the women's bantamweight title.

Peña also became the first woman in history to give birth and go on to win a UFC title.

Nunes entered the match off the back of a 12-fight win streak and as the clear favourite to retain her bantamweight title. As number one in the women's pound-for-pound rankings, many predicted an easy victory for The Lioness.

Nunes looked in control in the early minutes of the match and brought Peña down to the canvas but her submission attempts weren't strong enough for the determined American.

The second round was an exhilarating one and showcased a mammoth performance from Peña, who shocked the former champion and indeed, the world as she delivered a rear-naked choke to finish the match and dethrone the Brazilian.

"I told you. Don't ever doubt me again," Peña said after claiming the bantamweight title. "Willpower, strength and determination, it will take you places.

"I definitely expected a win and I'm just so grateful. The world is my oyster and you literally have the ability to do anything that you want in this life, and I just proved that tonight."

The UFC 269 co-main event marked the first time two mothers had met for a UFC clash and history-maker Peña joked that the promotion company should "create a new belt" in her honour.

"It’s got to be ‘Baddest Mom on the Planet,’" The Venezuelan Vixen said. "I’m not trying to take anything away from Amanda — she’s a wonderful mother. But I gave birth to my daughter. I feel like for giving birth, I am the first Mom-Champ. That means a lot to me."

Peña is reportedly interested in facing off against Valentina Shevchenko in the 125lb weight class. Should the fight go ahead, Peña will be looking to redeem the defeat the Kyrgyzstani-Peruvian dealt her back in 2017. But still on the high of her win in Las Vegas this weekend, she is not looking too far ahead at the moment.

"I have nothing to prove," Peña said after claiming the bantamweight title. "Everyone slept on me and I shocked the world."

By handing Nunes her first loss in more than seven years, Peña has achieved what the likes of Ronda Rousey and Holly Holm failed to do in the past. The Venezuelan Vixen's astonishing win will be a match talked about for many years to come.