Nathan Cleverly suffered a fifth stoppage defeat as Badou Jack ripped away his WBA 'regular' light-heavyweight title with a ruthless victory in Las Vegas.
The Welshman was making the first defence of the WBA belt that he won against Juergen Braehmer last October, but could not hold off the hugely impressive Jack, who claimed a version of a world title on his debut in the division.
From the opening bell, Cleverly tried to set a swift tempo with his stabbing jab, but Jack calmly countered with a thudding right hook.
'The Ripper' again showed his razor-sharp accuracy in the second round, ramming in right hands and slipping hurtful blows to the body.
Cleverly was breathing heavily by the third round, possibly feeling the effects of Jack's steady assault, and his defences unravelled in a torrid fourth.
A left hook visibly wobbled the legs of Cleverly, who was being punished with punches from all angles, and his bloodied nose was evidence of the brutal barrage.
Sensing the end was near, Jack resumed his onslaught in the fifth and referee Tony Weeks stepped in as Cleverly was caught by a succession of punches on the ropes.