American Justin Gaethje turned the tables on Ilia Topuria to claim a shock win and take the lightweight crown at the UFC Freedom 250 event on the lawns of the White House.
After Topuria edged a thrilling first two rounds on Sunday, Gaethje stunned the Spaniard with a crunching right hand before following it up with a brutal flurry of jabs that left his opponent’s face swollen and bloodied.
Topuria appeared to have trouble seeing and was checked by a doctor before continuing through the fourth, but his corner threw in the towel before the final round.
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“I cannot even believe it … I knew I was going to have to get through the first round, his skills are unmatched when he’s fresh,” Gaethje said.
“But my durability, my tenacity and my heart were going to carry me through.”
The bout headlined the first professional sporting event to be hosted at the White House, a key part of US President Donald Trump’s celebrations of the nation’s 250th anniversary.
In the co-main event, France’s Ciryl Gane dominated Brazil’s Alex Pereira before scoring a stunning second-round knockout win to become the interim UFC heavyweight champion.
Pereira, a former light heavyweight and middleweight champion, was looking to become the first UFC fighter to win titles in three divisions after stepping up to heavyweight.
Donald Trump has celebrated his 80th birthday with an Iran peace deal and a mixed martial arts event at the White House.
Also celebrating his 80th birthday, the US president announced an Iran peace deal just hours before the start of Sunday’s Ultimate Fighting Championship event, which was held amid thunderstorm warnings in Washington DC.
Immediately following the card, Trump was due to fly to a meeting of heads from the G7 group of leading democracies in Evian, France, where the settlement reached with Iran to end the four-month-long war was likely to dominate, with full details still to emerge.
The build-up to the cage-fighting event saw the president and UFC chief Dana White walk together from the Oval Office to the White House balcony overlooking the giant open-sided arena, nicknamed The Claw, on the South Lawn.
The national anthem was then played as a formation of fighter jets streaked overhead, sparking a cheer from the crowd and chants of “USA, USA”.
Trump then took his seat close to the signature octagon cage, where the seven fights were to be held.
Among the 4000 guests in the custom-built venue was British heavyweight boxing star, Tyson Fury, wearing a Donald Trump for prime minister baseball hat.
Meta boss Mark Zuckerberg was also spotted speaking to the president during a break in the action.
Others with cage-side seats were FBI director Kash Patel, acting US Attorney-General Todd Blanche and Speaker of the House of Representatives Mike Johnson.
Tens of thousands more watched the Freedom 250 bouts on a big screen in a park close to the White House, with some having travelled from across the country for the spectacle.
It made for some incongruous scenes with fighters pictured warming up inside the formal surroundings of the White House.
While the administration said the UFC would be covering the $US60 million ($A85 million) cost, official documents show seven agencies, including the Department of Homeland Security and the Federal Aviation Administration, had “allocated significant resources and manpower” to the controversial event, which was the subject of an unsuccessful legal challenge.
