The 32 year-old from Philadelphia, who held the 140lb title between 2006 and 2007, won every round of the contest to claim a comprehensive win as Whittaker admitted after the fight that he just didn’t want it no more.
After being put down in the fourth with a classy shot, the writing was on the wall for Whittaker, 39, and the veteran decided after the sixth that enough was enough and quit on his stool to hand the title to Hopkins.
Also on the bill, Edner Cherry continued his good form since losing a world title challenge to Timothy Bradley on points in 2008 by stunning Vicente Escobedo with a sixth round stoppage.
‘Cherry Bomb’ was seen as an ideal opponent for Escobedo to get his career back on track following his damaging loss to Adrien Broner last year, although Cherry ripped up the script to turn the tables on the Californian.
Bahaman-born Cherry, 30, controlled the fight from the word go, hardly giving 31 year-old Escobedo an opening and sent ‘Chente’ to the floor in the second with a crunching right hand.
From that point on there looked for only one winner and despite rallying at the end of the fourth, Escobedo was second best in the fifth and Cherry finished the job in the sixth with another hammer right hook.