Tony Bellew stopped David Haye inside five rounds of their rematch at London's O2 Arena, surely ending his rival's career in the process.
Haye was sent to the canvas three times as Bellew confirmed his superiority, and while Haye beat the count on each occasion, the fight had to be stopped in the fifth round with Bellew unleashing on a helpless opponent.
An emotional Bellew said: "I just want to say first and foremost, I lost my brother-in-law in August. He was sitting here tonight watching me. I swear kid, that every punch I threw was for you.
"He's been on my mind since August, and I just miss him so much."
Bellew was again keen to pay tribute to his beaten opponent, who started on the front foot but had no answer once Bellew upped the tempo.
"David Haye is an amazing fighter," he added. "I was hurt in that fight - he's got crazy power.
"He's a better fighter, he's a legend of the sport. I'm just happy I've won - against all the odds again."
The fight began with Haye on the front foot, perhaps edging each of the first two rounds on the scorecards, but he wasn't able to land clean shots as Bellew took his time, content to be selective and work behind his jab.
As things opened up in the third, Bellew landed a vicious left-right combination to send Haye to the canvas with 25 seconds of the third remaining, and the bell came to Haye's rescue as he was on the floor again soon after.
Coming out for the fourth, Haye was left to swing wildly in search of the stoppage but it was Bellew who continued to land the cleaner punches, ending the round as a 1/16 favourite having began the fight as the clear underdog once more.
Bellew had looked the more confident fighter from the outset, even if Haye had been more aggressive, and by the fifth it was the Liverpudlian who was in total control as he landed the cleaner, more hurtful punches.
The decisive blow came in the fifth when Bellew connected with a left hook, and while Haye got up for the third time, the referee was forced to end the fight soon after.
Haye said: "Tony boxed a great fight. Tony was the better man, and I couldn't quite make it happen.
"Tony Bellew is definitely my nemesis.
Asked whether this was the end of his career, Haye added: "I don't know. Tony Bellew boxed a fantastic fight. Take my hat off to him."