CARSON, Calif. -- Junior bantamweight world titleholder Naoya Inoue is nicknamed "The Monster" in his native Japan, and that's just what he looked like in his American debut on Saturday night.
Inoue, 24, retained his 115-pound belt for the sixth time, as he thrashed overmatched Antonio Nieves en route to a sixth-round knockout victory at the StubHub Center in the co-feature of the Srisaket Sor Rungvisai-Roman "Chocolatito" Gonzalez rematch.
Nieves had taken punishment, especially to the body, before his corner threw in the towel following the sixth round.
"I'm very happy with my performance. He was a brave warrior, but tonight, I was too good for him," Inoue said through a translator. "I'm very pleased to fight in the United States and thank HBO. I want to come back here to fight again soon. I will fight anybody, and I want to do it as soon as possible."
Inoue (14-0, 12 KOs) nearly knocked Nieves (17-2-2, 9 KOs) down with an onslaught of shots late in the second round, during which he also continually battered Nieves to the body.
He continued to dominate with an impressive array of punches, but he did a lot of damage with a regular body assault. Nieves flinched often as Inoue prepared to throw a punch and spent long stretches of the fight covering up to try to avoid the incoming.
Inoue continued to work Nieves over with body shots in the fifth round. They were audible at ringside. And then he landed a clean left hook to the pit of Nieves' stomach that knocked him down. Then, when the sixth round was over, the corner told referee Lou Moret that Nieves, 30, of Cleveland, was done.
"He is very strong, very quick," Nieves said. "He kept throwing the same combinations, but they never stopped. He's relentless in there."
Inoue was considered a prodigy when he turned pro in 2012. He won a junior flyweight world title in his sixth fight, and then moved up two weight classes to win a junior bantamweight title in by blasting out longtime titleholder Omar Narvaez in the second round in 2014.
Estrada edges Cuadras in eliminator
In a fierce fight between Mexican countrymen with a lot on the line, junior bantamweight Juan Francisco Estrada (36-2, 25 KOs) eked out a unanimous decision against former junior bantamweight titlist Carlos Cuadras (36-2-1, 27 KOs) in their world title elimination fight.
All three judges scored the fight 114-113 for Estrada, who scored a knockdown in the 10th round. But Hall of Fame ring announcer Michael Buffer initially announced Cuadras as the winner before returning to the mic moments later to make a correction as the crowd, which seemed partial to Estrada, went wild. Estrada, a former unified flyweight titleholder, was shocked when the scores went against him but happy when they were announced again.
"I was surprised when he announced Cuadras," Estrada said through a translator. "It had to be wrong. I felt like I was being robbed."
With the victory, Estrada earned a mandatory title shot against Srisaket Sor Rungvisai, who retained his world title by spectacularly knocking out former titleholder Roman "Chocolatito" Gonzalez in the fourth round of the main event.
Estrada had started very slowly, and Cuadras appeared to win many of the early rounds, but Estrada stormed back in the second half of the fight.
"He surprised me with his quickness in the early rounds," Estrada said. "Once I figured it out, I beat him bad the last six, seven rounds."
The action really picked in the back-and-forth sixth round, as they traded for much of the round. Estrada found success with his right uppercut, but Cuadras took the shots well.
Estrada seemed to really break through in the seventh round when he hammered Cuadras with several hard right hands that twisted Cuadras' head and knocked him back.
Cuadras, aggressive throughout the fight, connected with a powerful right uppercut early in the ninth round that rocked Estrada's head back. Moments later, he came over the top with a clean right hand that landed cleanly and snapped Estrada's head back.
Estrada responded in the 10th round by landing a clean right hand near Cuadras' nose that dropped him. Cuadras, 29, beat the count and appeared to shake off the knockdown rather quickly.
Estrada, 27, continued his late rally with a strong 11th and 12th rounds as he landed many clean shots against Cuadras, who had grown a bit sloppier with his punches as the fight wore on.
Cuadras was disgusted with the decision. He believed he was robbed last September in a decision that cost him his world title against Gonzalez, and he now felt that way again.
"I absolutely won the fight. I slipped. It was not a real knockdown," Cuadras said, though he got hit with a solid punch for the knockdown. "I can't believe this happened again. I want an immediate rematch. I'm very upset. I won the fight."
Former two-division world titleholder Brian Viloria (38-5, 23 KOs) scored a fifth-round knockout of Miguel Cartagena (15-4-1, 6 KOs) in a junior bantamweight fight.
Viloria had a very big fourth round in which he battered Cartagena and had referee Raul Caiz Sr. looking closely. Viloria backed Cartagena into a corner and teed off on with an avalanche of punches. When Cartagena escaped, Viloria chased him down and continued to pound him. In the fifth round, he continued to attack, and when he staggered Cartagena with an overhand right, Caiz stepped in and waved it off at 44 seconds.
Hawaii's Viloria, 36, a 2000 U.S. Olympian who went on to win junior flyweight and flyweight world titles -- four belts in all -- suffered a ninth-round knockout loss in a flyweight world title fight against Gonzalez in October 2015 and contemplated retirement. He returned for a win in Japan in March and recorded his second victory in a row against Cartagena, 25, of Philadelphia, which could set him up for a far more meaningful fight against one of the other top junior bantamweights who were on the card.
Kazakhstan's Ruslan Madiyev (10-0, 4 KOs), 24, a training partner of unified middleweight champion Gennady Golovkin and trained by Abel Sanchez, won a lopsided but hard-fought decision against Mexico's Abdiel Jose Ramirez (23-2-1, 21 KOs), 26, in their lightweight fight. Madiyev won on scores of 80-72, 79-73 and 79-73.
In a women's flyweight fight, Seniesa Estrada (11-0, 2 KOs), 25, of Los Angeles, won every round against Anahi Ramos, 28, of Mexico, in an action fight. Estrada won 80-72 on all three scorecards.
Los Angeles junior welterweight George Acosta (3-0, 1 KO), 20, rolled to a shutout decision against Derick Barthelemy (0-6-1), 32, of Portland, Oregon. All three judges scored the fight 40-36.
Welterweight Nick Frese (6-0, 5 KOs), 23, of Thailand, won a four-round decision against Nam Phan (3-3-1, 2 KOs), of Fountain Valley, California. The scores were 40-36, 39-37 and 39-37.