Naoya Inoue further enhances the opinion that he is the biggest pound-for-pound puncher in boxing with a second-round stoppage of Nonito Donaire.

Thirty-one months ago, the pair put on a classic bout at the same arena in Saitama, Inoue prevailing on points in a thriller with the WBA and IBF bantamweight titles on the line.

Those belts, as well as Donaire's WBC crown, were on the line in Japan on Tuesday, the veteran looking to build on what was an encouraging performance in the twilight of his career.

However, on this occasion, it was one way traffic. The thud of Inoue's punches could be heard from the opening bell, and Donaire had only offered a brief flurry before he was put to the canvas at the end of the first round.

Inoue had largely worked with his left hand before drilling Donaire with a surprise right, the 39-year-old looking stunned as he got off the canvas.

Sensing his opponent had not recovered, Inoue went for the finish in the second, Donaire withstanding numerous heavy blows that would have knocked out the majority of high-calibre fighters in the 118lbs division.

However, there was an inevitability about the early finish, Donaire initially stumbling backwards after a left hook before a combination finished the job in the corner, the referee waving off the fight before administering the count.

Inoue now advances to 23-0 with 20 stoppages, while Donaire drops to 42-7, this latest defeat possibly being the final outing of a hall-of-fame career.