Naoya Inoue takes out Stephen Fulton in eight rounds to become four-weight world champion

Naoya Inoue delivered a stunning performance to drop and stop Stephen Fulton to win the WBO and WBC titles in his first bout at super-bantamweight on Tuesday at the Ariake Arena in Tokyo.

Inoue has looked a dominant force in his rise from light-flyweight. He became an undisputed champion at bantamweight in his last contest and is now a unified champion at 122lbs, the fourth division in which he's held world titles.

Stepping up for his first bout at super-bantamweight, in Fulton Inoue was challenging the acknowledged top boxer in the division without a tune-up bout.

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Fulton was bringing his titles to Tokyo to take on the Japanese superstar, the newest and the biggest threat in the weight class, in his home country.

Neither man had met defeat before, Inoue now with a flawless 25-0 record, 22 of those wins by way of knockout and Fulton sporting a 21-0 (8) ledger going in.

Inoue, for all his acclaim, remains a hungry fighter and he began the contest eagerly. Unfazed by Fulton initially claiming the centre of the ring, Inoue padded down the champion's jabs.

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Then Inoue, slotting in thudding jabs of his own, hit Fulton's head and body. His confidence only grew and Inoue could build combinations on to those shots.

He quickly covered the distance between them, catching up to Fulton when the American tried to back away.

Inoue opened up with salvos of punches in the second round, disrupting Fulton and making his power felt at 122lbs.

To broadcast his self-belief, Inoue even tapped his chin, showboating for just a moment. He sunk power into his right cross, a thudding blow that Fulton blocked on his gloves when he could. But too often for the champion, Inoue was getting that shot through.

Fulton steadied himself in the fourth round, intercepting his challenger with jabs. But he was finding it difficult to fight the contest on his terms.

Inoue landed ferocious combinations in the fifth round, catching the body spitefully even if Fulton did manage to land with a one-two of his own.

Inoue drove him back with three long punches and Fulton found himself trading with the "Monster" at the end of the sixth round, pushing forward just to stall his challenger's momentum.

But he could not ward off Inoue. Inoue just took his ferocity up to a new level, continuing to break through the American's guard.

He hurt the champion in the eighth round. Inoue snapped in a one-two, the right cross buckling Fulton. At once Inoue leapt through with a wide left sweeping across to put Fulton down.

He leapt onto the ring post to celebrate early, even though Fulton rose to continue. Perhaps he knew that he would not let Fulton off the hook.

He resumed his work, pounced on Fulton instantly and took him to a corner. He pummelled Fulton there. Inoue's hooks flew in from either hand, he linked a blast of punches together and the referee stepping in to wave it off just as Fulton sank back to the canvas.

It was a spectacular finish for the new unified super-bantamweight champion.

"Last year I became an undisputed champion and returned all the belts to become a super-bantamweight. Everything I was thinking about in my mind was to fight him [Fulton] earlier this year, but unfortunately, I got injured and had to postpone the fight. I'm sorry to my team, to Fulton's team but thank you for accepting this fight once again," he said.

"I am so happy right now."

Ramirez defends

Cuba's Robeisy Ramirez made the first defence of his WBO featherweight title on the second-billed fight, ruthlessly disposing of Japan's Satoshi Shimizu.

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Shimizu was an Olympic bronze medallist at London 2012, but Ramirez was twice an Olympic champion as an amateur and, after a misstep when losing his first pro fight, has looked impressive as he has risen to title class.

A southpaw - like Shimizu - Ramirez soon pegged back his taller opponent. He selected heavy combinations and steered the challenger away with a heavy lead hook.

His uppercuts were damaging. In the fourth round a feint let him blast an excellent left uppercut through.

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In the next round he used that shot to hurt Shimizu, dropping him heavily. Rising but with blood leaking from his nose, Shimizu could not escape and Ramirez found the finish at 1-08 of the fifth.

Yoshiki Takei and Kanamu Sakama were both stoppage winners on the undercard at the Ariake Arena.

Takei stopped Ronnie Baldonado with a body shot in the third round, while Sakama finished Ryu Horikawa with 10 seconds left in their contest.

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Next for Inoue?

Naoya Inoue could be looking to go undisputed in a second weight class next.

Marlon Tapales, the holder of the IBF and WBA titles at 122lbs, was ringside in Tokyo and stepped into the ring to challenge him after the bout.

"I want to fight Naoya Inoue because I want to prove that I am a champion," Tapales declared.

Inoue is ready to take that fight. He answered: "Let's do it this year!"