In what was billed as a battle of the organisation's top two contenders, Namibia's Nakathila looked anything but a top contender, with the 23-year-old Stevenson (16-0, 8 KOs) dominating from the outset in his third bout at 130 pounds.

American Stevenson, a 2016 Olympic silver medalist, won by identical scores of 120-107 from all three judges while pound-for-pound great Terrence Crawford watched from just behind his prodigy's corner.

Crawford helped Stevenson prepare for the fight with sparring sessions during his training camp.

Nakathila (21-2, 17 KOs), who struggled to land punches the entire fight, missing with big, looping right hooks, lost for just the second time in his career.

Stevenson has made it crystal clear he wants a shot at WBC champion Oscar Valdez, but likely has a date with WBO titlist Jamel Herring later this year.

In the co-featured main event, two-weight world champion Jose Pedraza (28-3) won by TKO after the eighth round, when Julian Rodriguez's (21-1) cornermen told referee Kenny Bayless their fighter couldn't continue with his left eye closed.

Australian Associated Press