Naoya Inoue recovered from a first-round knockdown to beat Luis Nery in the sixth round and defend his titles and maintain an unbeaten record.
Inoue, the undisputed world super-bantamweight champion, had never been knocked down before Nery floored him with a left hook just two minutes into the bout.
But the 31-year-old Japanese, who has held world titles at four different weights and two undisputed, picked himself up to secure a sixth-round victory after putting his Mexican opponent down for the third time with a brutal right hand.
Nery stunned both the champion and a 55,000 sell-out crowd at the Tokyo Dome in Japan, where Buster Douglas shocked Mike Tyson in 1990, when barely two minutes into the fight he floored Inoue with a swinging left hook.
However, Nery had to pick himself up from the canvas in the second after the Japanese fighter caught him with a short left.
Inoue scored heavily with the straight right in an impressive third-round display and began to showboat in the fourth as a frustrated Nery repeatedly missed the target with his big punches and was peppered with his opponent's jab and body shots.
The 29-year-old's work became increasingly untidy as he tired and after being warned for leading with his head, he was felled by another left hook in round five, and the end arrived midway through the sixth.
Inoue, nicknamed 'The Monster', had opened up Nery with a lethal combination and having forced him on to the ropes, dispatched him with a vicious right hand to end the contest and complete a successful second defence of the titles he won in December.
It was the 27th win of his unbeaten career and 24th knockout, and just a second defeat for Nery in 37 bouts.
Additional reporting by Press Association.
