Naoya Inoue KOs Paul Butler in 11th round to win undisputed bantamweight championship

There was never any doubt who was the best 118-pounder in the world, but now Naoya Inoue has the official distinction.

Inoue, FightNights.com's No. 2 pound-for-pound boxer, won the undisputed bantamweight championship with an 11th-round KO of Paul Butler on Tuesday in Tokyo.

The fight, however, was a bore for the most part. Inoue pressed the action, but Butler seldomly threw a shot and was in survival mode from the onset. And even he couldn't succeed in that endeavor.

The Japanese superstar hurt Butler with a two-punch combination, a vicious right hook to the liver followed by a left hook upstairs that sent Butler wobbling into the ropes. Moments later, Inoue uncorked a flurry of power shots that sent Butler to the canvas for the 10-count at 1:09 of the penultimate round.

Inoue (24-0, 21 KOs) entered the ring with the WBA, WBC, and IBF titles at 118 pounds, while Butler (34-3, 14 KOs) came in with the WBO belt in his possession, although he had yet to make a title defense. The 34-year-old Englishman outpointed Jonas Sultan over 12 rounds in April to win the WBO interim title and was later elevated to full champion after then-titlist John Riel Casimero was stripped.

Inoue, 29, stripped Butler of his windpipe to become the first undisputed champion from Japan since the four-belt era began in 1983.

Inoue (24-0, 21 KOs) entered the ring with the WBA, WBC and IBF titles at 118 pounds, and he added Butler's WBO belt to become the first undisputed champion from Japan since the three-belt era began in 1983.

"This is the proudest moment of my career," Inoue said through an interpreter. "I am honored to become undisputed champion at bantamweight. This is my last fight at this weight. I am excited to see what is in store [at 122-pounds]."