Julianna Pena stopped Amanda Nunes by submission with a rear naked choke in the second round at UFC 269 on Saturday night, claiming the bantamweight title from the long-reigning two division champion in one of the biggest upsets in recent UFC history.

Charles Oliveira also defended his lightweight title for the first time with a third round stoppage victory over Dustin Poirier by standing rear naked choke in the main event.

Pena (11-4) was a 10-1 underdog against the vaunted Nunes, widely considered the greatest fighter in the history of women’s mixed martial arts.

Nunes had won 12 consecutive fights since 2014 and reigned simultaneously atop the 135-pound bantamweight and 145-pound featherweight divisions for three years.

After Nunes largely dominated the first round with two knockdowns and superior striking, Pena shockingly hurt Nunes with punches in a slugfest start to the second round. Pena then got Nunes to the ground, got her back and forced the champion to tap out with a choke around her neck with 1:38 left.

“It feels crazy,” Pena said. “I definitely expected to win, but the world is my oyster.”

Pena had won just two of her four fights over the past five-and-a-half years, and the Spokane native got the title shot as one of the few legitimate 135-pound fighters that Nunes hasn’t already beaten.

Nunes was fighting for only the third time in two years after making two featherweight defences since her most recent defense of her bantamweight belt in December 2019.

Few opponents had even given her a stiff challenge since her second victory over current flyweight champ Valentina Shevchenko by split decision in 2017.

Nunes is almost certain to be granted a rematch with Pena, which could affect the UFC plans of Kayla Harrison, the two-time Olympic judo gold medalist who has gone 12-0 in the Professionals Fighters League since taking up MMA in 2018.

Harrison, a promotional free agent, attended UFC 269 and appeared to be just as shocked as the rest of the crowd by Pena’s win.

After Pena’s upset, Oliveira (32-8, 1 no-contest) survived a rough fight with Poirier (28-7, 1 no-contest) to improve to 10-0 with nine stoppage victories since 2017.

Poirier battered the champ with punches in the first round and knocked him down twice, but Oliveira took control on the ground in the second round with a series of vicious elbows. He finished the fight with 3:58 left in the third by attaching himself to Poirier’s back and forcing him to tap while standing up.

Oliveira finally claimed the belt last May in his 28th UFC fight — the longest wait for a title in the promotion’s history and the culmination of an epic journey by a Brazilian veteran who overcame poverty and childhood illness to become an elite jiu-jitsu practitioner and mixed martial artist.

Oliveira set the UFC record for stoppage victories by beating Michael Chandler with punches, and his finish of Poirier increased the record to 18.

Poirier already had a spectacular 2021 with his two victories over Conor McGregor, erasing the vaunted former champion’s winning mystique and making two enormous paychecks for decisive stoppage wins.

Poirier’s only other loss in his last 11 fights since 2016 was to Khabib Nurmagomedov, who took away Poirier’s interim lightweight title before retiring undefeated.

Earlier at T-Mobile Arena, New Zealand flyweight Kai Kara-France stopped former bantamweight champ Cody Garbrandt with a series of massive strikes in the first round.

Former bantamweight champion Dominick Cruz also rallied for a unanimous decision over Pedro Munhoz. The oft-injured Cruz hadn’t won since 2016 before claiming back-to-back victories in 2021.

Australian heavyweight prospect Tai Tuivasa won his fourth consecutive bout by stoppage with a violent second-round knockout of Brazil’s Augusto Sakai.

Tuivasa celebrated by climbing atop the cage and doing a shoey from somebody else’s shoe, and he repeated the celebration on his way out of the arena.