George Kambosos Jr stunned the world by out-gunning Teofimo Lopez to claim the unified lightweight championship in a bitter grudge match in New York.
But the Australian's incredible victory was slightly overshadowed by the reaction of his 'classless' opponent who snatched the microphone to say 'I won'.
Kambosos in his victory speech showed respect to the American, 24, after the brutal split decision calling him a 'true champ', but Lopez cut him off.
George Kambosos Jr (left) victory was slightly over-shadowed by the reaction of his 'classless' opponent Teofimo Lopez (right) who snatched the microphone post fight to say 'I won'
'He's a hell of a fighter, but I won tonight, man,' Lopez said.
'Everybody knows that. The referee raised my hand. I won tonight. I don't care what anybody says, I won tonight.
'I ain't no sore loser. At the end of the day, I take my wins, I take my losses. I'm a true champion. I came out here. I did what I had to do.'
But with deep cuts and swelling over both his eyes, the Sydneysider called him 'delusional'.
Pictured: Teofimo Lopez
'Look at your face. But I gave you the respect. I came here I gave you the respect in the ring and I won the fight. Take it like a champ. Move on. We can do it again in Australia in front of 80,000 people,' Kambosos said.
'All respect to him. Madison Square Garden, New York, I love yas all.
'All respect to Teofimo. He's a great kid. The build-up was the build-up. We're both competitive, we're both young guys.'
The boxing world blasted Lopez for not showing enough respect to the Australian after being beaten.
Two-time Olympic gold medalist and multiple world championship winner Claressa Gwoat Shields said: 'Champions take losses really hard... But umm this ain’t it.'
Renowneed boxing journalist Dan Rafael wrote on Twitter: 'Lopez crashes Kambosos interview and says he won the fight. Not a good look.'
ESPN's Mike Coppinger posted that there were 'Big-time boos for Teofimo Lopez, who claims he was robbed and won 10 of the 12 rounds.'
George Kambosos Jr has etched his name in Australian boxing folklore with a stunning points victory over Teofimo Lopez in their unified lightweight championship grudge match in New York
As he boldly predicted during the spiteful build-up, Kambosos is the new undisputed world champion after defying the odds to strip the previously unbeaten Lopez of his WBO, WBA and IBF titles with a mighty performance at Madison Square Garden
As he boldly predicted during the spiteful build-up, Kambosos is now the new undisputed world champion after defying the odds to strip the previously unbeaten Lopez of his WBO, WBA and IBF titles with a mighty performance at Madison Square Garden.
The 28-year-old from Sydney is the first Australian boxer in history to win three world title belts in one bout, a feat that eluded even Jeff Fenech and Kostya Tszyu, both widely recognised as the country's two greatest pugilists.
Kambosos was a huge underdog to beat Lopez (16-0, 12KO) with the American adamant he'd take the challenger out in the first round.
Kambosos was having none of it, insisting three years serving as legendary Manny Pacquiao's sparring partner in the Philippines had steeled him for the biggest fight of his life.
'Back yourself, believe in yourself,' he said after winning on
