Former two-time world champion Roger Mayweather battered Livingstone Bramble, also a former world champion, at 1:10 of the fifth round of their scheduled 10-round welterweight bout in Las Vegas.
Mayweather, 31, the World Boxing Assn. junior lightweight champion in 1983 and '84 and the World Boxing Council super-lightweight titleholder from 1987-89, won with a barrage of combinations. Bramble's corner man, Janks Morton, got on the ring apron, which disqualified Bramble under Nevada rules.
Mayweather has an 8-2 record since being dethroned almost four years ago and an overall mark of 43-8 with 28 knockouts.
Bramble, 24-11-2 with 22 knockouts, has lost three in a row and eight of his past 12 since 1989.