Joshua Buatsi extended his unbeaten record with a brutal knockout win against Daniel Blenda Dos Santos.
The light-heavyweight, a bronze medallist for Great Britain at the 2016 Olympics, was dominant in only his second outing since August 2019.
He floored Dos Santos with a flurry in round two, and a hard right knocked the Frenchman out in the fourth.
"We've seen unknown opponents come and beat guys," said Buatsi, 28, after the Manchester Arena win.
"I took him seriously. I landed the shot at the right time. Most importantly I hope he is OK."
Much is expected of Buatsi, given his amateur pedigree and the efficient manner of his displays in his 14 professional wins.
He has moved to link up with decorated American trainer Virgil Hunter, but little could be gleaned from this outing as it was quickly evident he was a class apart from Dos Santos.
The travelling fighter - who had won all 15 of his previous fights - sobbed in the ring after.
BBC Radio 5 Live boxing analyst Steve Bunce described him as "inconsolable" and "broken", and Buatsi moved to spend time embracing his rival minutes after the finish.
Hunter said he hopes to make Buatsi ready for a world title shot in about 14 months, while promoter Eddie Hearn said his charge will fight again in July and must now become more active.
"What we must do is capitalise on the ability to gain momentum in Buatsi's career," said Hearn.
"The next one has to be a step up. We need to find that next level, but we must keep momentum. He has been out of the ring for seven months and has a new trainer, so that was a big box ticked."
'Tears and time to take a risk' - analysis
BBC boxing correspondent Mike Costello
Dos Santos fell very, very heavily. That was a punishing finish. Dos Santos is not so much crying but sobbing. There is agony in his face after the first defeat of his career.
BBC Radio 5 Live boxing analyst Steve Bunce
Buatsi needed something nasty. It might sound cold but that is the business we are in. It was the message he had to send, not just to the top three or four Brits but to the other light-heavyweights out there.
There are an awful lot of good, tough light-heavyweights, who will give him the rounds he now needs. At 28 and five years after the Olympics, it's time to take a risk.
Brilliant Cunningham stuns Yafai
The Manchester fight card also featured three European title bouts.
Belfast's Tommy McCarthy, 30, knocked Romania's Alexandru Jur down in the fourth round and did so again to end the contest and defend his cruiserweight title in the sixth.
"I've been saying I would love to have a crack at any of the world champions. If none of the champions, Chris Billam-Smith can get it," said McCarthy.
His promoter Hearn added: "That fight is made. Tommy has already put pen to paper for that fight, so has Billam-Smith. That will be a huge fight this summer, a proper domestic fight."
In a thrilling fight, Doncaster's Jason Cunningham upset the odds to win the European super-bantamweight title from Gamal Yafai.
The 31-year-old floored Birmingham-born Yafai three times and stood up to a late fightback from his rival in a superb display, earning a unanimous 115-110 114-111 114-111 points win.
"Setback after setback, no big promoter behind me, I've done it the hard way," said Cunningham. "I'm always written off, always. I had three weeks' notice. That's got to be my best performance."
And Britain's Lerrone Richards was slick and accurate in a classy display in easing to a unanimous points decision to land the vacant European super-middleweight title against Italy's Giovanni De Carolis.