Dereck Chisora stopped fellow Briton David Price in the fourth round of a frenetic heavyweight clash at The O2 in London - then targeted Ukraine's Oleksandr Usyk.
Former world title contender Chisora, 35, unsettled Price at the end of the third round with two right hooks and unloaded again in the next round to send his opponent to the canvas.
Although a dazed and wobbled Price, 36, got up during the count, his corner threw in the towel to end the fight.
Usyk, 32, was the undisputed cruiserweight champion before he moved up to heavyweight this year.
He won his first fight in the division earlier this month when he defeated Chazz Witherspoon, a late replacement for Tyrone Spong who had returned an adverse doping test.
David Haye, the former two-weight world champion who now manages Chisora, told Sky Sports: "I like the Oleksandr Usyk fight. That would be a fantastic fight.
"If he fights Oleksandr Usyk, he's right up there for a heavyweight title shot. A title shot is what he wants."
Earlier, ex-IBF featherweight champion Lee Selby beat former three-weight world champion Ricky Burns on points.
Elsewhere on the undercard, Lawrence Okolie took the European cruiserweight title from Belgian Yves Ngabu, who had a 20-0 record.
The fight was stopped in the seventh round after the 26-year-old landed a left hook and then a big right hand which left Ngabu unsteady on his feet.
"I could hear him get more and more tired," Okolie told Sky Sports. "If I hit any cruiserweight on the chin then they're going to go."
"I believe he will breeze his way to a world title," added promoter Eddie Hearn. "Watch him become a world champion in 2020."
Another Briton, Conor Benn, defended his WBA continental welterweight title with a fourth-round knockout of Belgian Steve Jamoye.
Benn, 23, the son of former middleweight and super-middleweight world champion Nigel Benn, ended his opponent's night with a fierce right hook.