INGLEWOOD, Calif. (AP) -- Amanda Nunes knocked out Cris "Cyborg" Justino 51 seconds into the first round at UFC 232 on Saturday night, ending the featherweight champion's 13-year unbeaten run with one of the most surprising victories in mixed martial arts history.
Jon Jones also reclaimed his light heavyweight title in his return from a 17-month cage absence, stopping Alexander Gustafsson with strikes on the ground in the third round.
Nunes, the UFC's bantamweight champion, made history when she moved up 10 pounds to challenge Justino (20-2), widely considered the world's greatest female fighter. Nunes is the third fighter in UFC history to hold two title belts simultaneously, joining Conor McGregor and Daniel Cormier.
"I knew this was happening, I told you all!" Nunes said. "Cris is a great fighter, nothing but respect. It was an awesome opportunity to share the octagon with her. I'm very thankful to her for this. I'm the new 'champ-champ.' I said that before, and now I'm just achieving this dream."
Nunes (17-4) was thought to be an undersized underdog, but she seized her second title belt by overwhelming her fellow Brazilian. Nunes buckled Justino's knees in the opening seconds, and she eventually knocked down Justino twice.
She ended the fight spectacularly with an overhand right to the ear, putting Justino face-down on the canvas.
Just six days after the UFC moved the entire 232 card from Las Vegas to the famous Forum south of downtown Los Angeles, Jones (23-1, 1 no-contest) closed the show with a methodical dismantling of Gustafsson (18-5). The bout was a rematch of Jones' toughest fight, a thrilling decision in 2013 over Gustafsson.
But in Jones' first fight since completing his second drug-related suspension, the star picked apart Gustafsson with kicks in the first two rounds. He got a takedown in the third and finished the fight with several brutal shots to Gustafsson's head on the ground.
"It was always about being the champion again," Jones said. It was never about the opponent, nothing personal. I'm just happy with my belt, and for now I want to go back to the gym and improve my game."
The UFC made the extraordinary decision to move its show 280 miles to California to keep Jones on the card. The former champion recently tested positive for low levels of a banned steroid, but California regulatory officials didn't consider the result serious enough to keep the long-troubled star out of the octagon, while Nevada's commission did.
The 31-year-old Jones had fought only twice in the previous 47 months, losing an enormous chunk of his fighting prime due to his misbehavior. He held the UFC's 205-pound title twice before, but had it stripped both times.
Jones returned from his first doping suspension with a stoppage of Cormier in July 2017 to reclaim his light heavyweight title, but he lost the belt again after testing positive for steroids.
A capacity crowd of 15,862 in Southern California watched another groundbreaking achievement by Nunes, the ferocious brawler who calls herself "The Lioness." Nunes also knocked out Ronda Rousey in less than a minute two years ago.
"I'm taking care of myself, working hard physically and mentally," Nunes said. "I felt stronger in this division, more powerful, and continued to be very fast. I don't know what comes next. Now I want to celebrate with my friends and family in Brazil."
Nunes' punching power is often too much for her male sparring partners, and she carved up Justino with astonishing ease despite a size disadvantage. Justino had won 20 consecutive fights since her MMA debut in 2005, and she had dominated since the inception of the UFC's 145-pound division, which was created largely as a showcase for Cyborg's talent.
Earlier, Australian featherweight prospect Alexander Volkanovski (19-1) won his 16th straight bout in the PPV opener, stopping veteran Chad Mendes with right hands in the second round of a back-and-forth bout. Michael Chiesa also won his welterweight debut with a second-round submission of former champ Carlos Condit, who lost his fifth straight fight.
Former UFC lightweight champion BJ Penn tapped out for the first time in his MMA career, losing to Brazilian jiu-jitsu whiz Ryan Hall on a heel hook in the first round. Penn (16-13-2), an MMA pioneer who turned 40 this month, is 0-6-1 in his last seven fights since 2010.
Despite the late move to LA, the UFC sold out the Forum after just six days of ticket sales. The crowd included Justino friend Halle Berry, Dolph Lundgren, David Spade, NL MVP Christian Yelich of the Milwaukee Brewers, Travis Barker, Mick Foley and Amber Valletta.