Undisputed champion Inoue stops injured Doheny to retain titles
The unbeaten Inoue was declared the winner when Doheny was left hobbling and unable to continue following a barrage to the body from the man nicknamed "Monster".
Inoue took his record to 28-0 with 25 wins by knockout.
He was making his second defence since becoming the undisputed super-bantamweight world champion last December.
He is just the second man to become undisputed world champion at two different weights since the four-belt era began in 2004. American Terence Crawford was the first.
Inoue was fighting for the first time since he beat Mexico's Luis Nery in front of 55,000 fans at the Tokyo Dome in May.
That fight saw Inoue knocked down for the first time in his career but he never looked in serious danger against Doheny.
Inoue had to be patient against his cautious opponent but he began to land some big body blows as the fight progressed.
The bout came to an abrupt halt when Doheny suddenly began limping about 20 seconds into the seventh round, having appeared to injure his hip.
He was unable to walk and had to be helped from the ring by his team.
Doheny, who held the IBF super-bantamweight world title from 2018 to 2019, saw his record drop to 26-5, with 20 KOs.
On the undercard, Japan's Yoshiki Takei retained his WBO world bantamweight title with a unanimous decision win over countryman Daigo Higa.
Takei was making his first defence after taking the title from Australia's Jason Moloney in May.
