Audley Harrison began the process of restoring his reputation by winning his grudge re-match against fellow Briton Danny Williams inside three rounds.
Harrison picked Williams off from the first bell
Harrison was widely criticised after a lame performance in losing a split decision to Williams 12 months earlier.
But in the first round at London's ExCel Arena, a stunning left left Williams with a badly cut nose.
Williams was cut under his left eye in the second before Harrison claimed a technical knockout in the third.
Williams had taken the Commonwealth heavyweight title by beating Harrison in a split decision one year ago, although that belt was taken from Williams by Matt Skelton in July.
Skelton was due to fight Harrison here, at London's Excel, but he withdrew through injury so Williams stepped in at a week's notice for a re-match of that bout last December, which ended in bitter recriminations for Harrison.
The pair had clashed at the pre-fight weigh-in, and Harrison continued that aggression inside the first round as he opened up Williams' nose.
After two minutes of the second round, the fight was stopped so the referee could study Williams' face - by now a bloody mess with cuts across the nose and underneath his left eye.
Williams persuaded everyone he was fit to continue, but Harrison continued to take the fight to his opponent for the remainder of round two.
Williams' corner desperately tried to repair the damage ahead of round three, but his face looked like that of a man who had gone 12 rounds, rather than two.
Williams knew there was a danger that his cuts might result in an early stoppage, so he had a real go at knocking Harrison out at the start of the third.
In 2007 I will win the world title, in 2008 I will be undisputed
But Harrison was the one who claimed the knockout, sending Williams to the canvas with an uppercut.
Williams got up for one more go, but he was hit with yet another uppercut, prompting the referee to end the contest after two minutes, 32 seconds of that round.
"I have come back to the same venue after a torrid time last year and have done a job," Harrison told ITV after the fight.
"In 2007 I will win the world title, in 2008 I will be undisputed. You saw today I have definitely got the skills.
"People say I've got no heart and am petrified. The bottom line is that we all have bad days at the office.
"Last year I was not in the right place. I came back today with my closet cleared out. Boxing is what I want to do and let me go on in my career."