Bernard Hopkins once again made history by becoming the oldest boxer to unify a weight division after adding the WBA light-heavyweight crown to his IBF title with a split-decision victory over Beibut Shumenov.

Hopkins, already the oldest man to win a recognised world title, continues to confound his critics at 49 and once more beat a much younger man in Washington.

However, a split-decision verdict - two scores of 116-111 in his favour against 114-113 in Shumenov's - did not reflect his dominance.

The American made a typically sluggish start but came on strong from the third round onwards and knocked his 30-year-old foe down with a punishing right in the 11th.

Hopkins, who has not stopped an opponent in nearly a decade, could not finish off the Kazakh but finished well and was given the nod to improve his record to 55 wins from 65 fights, with six defeats, two draws and two no contests.

On the undercard, Shawn Porter put himself on a collision course with British welterweight Kell Brook this summer after retaining his IBF belt with an impressive fourth-round stoppage of Paulie Malignaggi.

Brook is the mandatory challenger for Porter's strap and it was agreed he would fight the winner of Saturday night's bout.

Porter proved too strong for the seasoned Malignaggi, who was sent crashing through the ropes and onto the ring apron after a vicious attack from the champion, which prompted the referee to halt the contest midway through the fourth round.

Porter would not look ahead specifically to a showdown with Brook but promised to live up to Malignaggi's prediction of greatness for him.

"I'm going to enjoy this and let my team handle what is next. I'm sure they will all communicate. We'll come up with the next game plan and we'll tackle it," he told Showtime.

"Paulie wished me the best and said, 'Make sure they know that I lost to a great champion. Go out there and be great'. I am going to honour his words and his wishes."

Hopkins, meanwhile, compared himself to one of the sport's all-time greats following his momentous win.

"I describe my legacy like a Joe Frazier," he said. "We get knocked down but we get back up.

"I'll let the historians analyse and debate over the years as I grow a deeper grey beard watching soap operas. I'll let them break down my legacy."