WBO super flyweight champion Naoya Inoue made his U.S. debut in style Saturday, hammering seventh-ranked Antonio Nieves by a sixth-round technical knockout to defend his title for the sixth time.

Inoue, 24, controlled the bout from the outset, knocking his 30-year-old American opponent down in the fifth and didn't let up the following round.

Boxing: N. Inoue defends super flyweight title for 6th time with TKO                                                                                                                                                    (Getty)

After the sixth having seen enough, Nieves' corner threw in the towel. All three judges had Inoue comfortably ahead 60-53 through the sixth at StubHub Center.

"It wasn't the sweetest of wins, but I'll take it and build on this for the next one," Inoue said. "There wasn't much I could do when he was running from me the whole time."

"I managed to get in shape despite being in a different environment here in America and I felt sharp."

Inoue had a strong second round, when he had Nieves backed into the corner where he threw a flurry of punches to decimate the challenger.

Boxing: N. Inoue defends super flyweight title for 6th time with TKO                                                                                                                                                  (Getty)

But Inoue, so locked into the fight, mistook the 10 second warning with the bell at the end of the round and laid off Nieves.

"I was into it -- too into it, actually," Inoue said. "It was kind of a waste, I'll admit that."

Nieves wasn't spared much longer, however, when Inoue floored him in the fifth with a hard left to the body. Nieves could only flee as Inoue tried to finish him in the sixth and was saved by the bell, his camp telling the referee that Nieves' night was over.

Inoue took his record to a perfect 14-0 including 12 knockouts, Nieves now 17-2-2. Inoue's next opponent could be Thailand's Srisaket Sor Rungvisai, the WBC champion in his division who was on the same card this night.

In the main fight, Srisaket knocked out Nicaraguan hero Roman Gonzalez in the fourth round to hold on to his title.