Tyson Fury recovered from a second round knockdown to knock out Steve Cunningham in the seventh round of their heavyweight clash at Madison Square Garden.
It was only the second time in the Briton's career he had had to pick himself up off the canvas, but he recovered strongly to go 21-0 and set up a final eliminator against Kubrat Pulev - with the winner of that contest to face Wladimir Klitschko.
This fight was billed as Fury's toughest test with Cunningham a two-time world champion at cruiserweight, with eight world title fights behind him.
And it all looked to be a step too far after an uppercut put him on the canvas in the second before his own uppercut followed by a sickening right hook two minutes, 55 seconds into the seventh round ended the contest.
Fury had a considerable seven-inch height advantage and used that to full effect early on as the American struggled to get close in the opening round, although Fury's lack of discipline showed as he pushed Cunningham after the bell, with the referee issuing a warning.
Seconds into the second and the Manchester fighter was put on the ground for just the second time in his career.
Cunningham caught Fury with a swinging right hand over the top which although failed to make full contact was enough to put the Briton on the floor.
Fury dusted away the cobwebs and straight jabs kept his opponent at bay, but in the third Cunningham had better success inside, while a blow in the fourth had Fury again in trouble.
Fury's antics were starting to annoy the referee and he took a point off the 24-year-old for going in with his head in the fifth.
A right uppercut put Cunningham under pressure as Fury began to assert his authority on the contest.
In the seventh a bodyshot and an uppercut clearly had the 36-year-old in trouble before a right hook landed plumb on Cunningham's chin and the American had no chance of beating the count.
It was the first time in the American's career that he had been stopped and Fury was keen to praise his opponents before turning the attention to his own performance.
"It's one of those things, you can't go swimming and not get wet h- e put on a good fight," Fury said.
"I got caught with a big swinging right. You have to get up, this is a learning experience.
"That was a good hook to the side of the jaw, it was a matter of time until I got hold of him and when I caught him it was curtains."
Rarely lacking in confidence, Fury proceeded to sing for the audience and although he proved he can mix it with international class fighters, the blow which put him on the floor shows there is plenty of improving left to do if he is to seriously challenge a Klitschko.