Denis Lebedev stopped Roy Jones Jr. with 10 seconds remaining in the 10th and final round of what had been a competitive cruiserweight fight Saturday in Moscow.
Lebedev (22-1, 17 knockouts) had Jones (54-8, 40 KOs) pinned against the ropes when he landed a series of brutal punches that prompted referee Steve Smoger to stop the fight.
Jones, 42, fell face first to the canvas after that and lay there unconscious for several minutes.
Jones, once regarded as the best fighter in the world, has now lost three consecutive fights. He was stopped in one round by Dennis Green in 2009 and then was easily outpointed by Bernard Hopkins last year.
Lebedev rebounded from a split-decision loss to WBO titleholder Marco Huck in December.