Japanese boxing champion Inoue Naoya has vowed to train hard so he can do his best in the super bantamweight class.

Inoue fought the Philippines' Marlon Tapales, who held the super bantamweight titles for the World Boxing Association and the International Boxing Federation, on Tuesday. Inoue already held the titles for the World Boxing Council and the World Boxing Organization.

Inoue knocked out Tapales in the 10th round, becoming the second male boxer to win all four major titles in two weight divisions. He unified the four major bantamweight titles last year.

Inoue, known to his fans as "Monster," spoke to reporters on Wednesday at the gym in Yokohama he belongs to.

He said he had to stay vigilant until the end as Tapales aimed to knock him out, but that he enjoyed the match.

The 30-year-old said he watched video of the match twice. He said some people described his punches as rough, but that it was a highly technical fight and he learned some things.

Inoue said he would give himself 70 points out of 100 for his achievements so far. He said he still has 30 more points to get and that he hopes to do so by using what he discovered in his latest match.

He added that he does not think he needs to force himself to change his weight class.