Bernard Hopkins added the WBA belt to his IBF title with a masterful points win over Beibut Shumenov in Washington.
The 49-year-old Hopkins, boxing's oldest world champion, confounded the younger Shumenov with his wily ring skills, flooring him in the 11th on the way to a split decision win.
He becomes the oldest man to unify world titles and can add this record to a long list of achievements, which includes numerous world title wins.
Shumenov, who is 19 years younger than the American, held his own in the early stages, but Hopkins started to dictate the pace.
His awkward style continued to frustrate Shumenov and Hopkins clinched the Kazakh to prevent him from fighting at close quarters.
Hopkins still retains enough power to hurt his opponents as he dropped Shumenov in the 11th with a punishing right hand.
But he was denied a first stoppage win in over a decade, with Shumenov standing firm until the final bell.
One judge strangely scored it 114-113 in Shumenov's favour, but Hopkins' dominance was reflected in the other two scores of 116-111.
When asked about his momentous win, Hopkins compared himself to one of the sport's all-time greats.
"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."