Antonio Tarver beat Roy Jones Jr by unanimous decision in Tampa on Saturday and almost certainly ended the career of one of boxing's all-time greats.
It was their third fight, Jones having won the first on points in 2003 only to be knocked out in the rematch in 2004.
Jones showed some glimpses of his brilliant best in the first half of the fight but faded badly down the stretch.
Tarver, who used his jab to great effect, had Jones in trouble in round 11 and fully deserved his victory.
The judges awarded Tarver the fight 116-112, 116-112 and 117-111.
Tarver improved to 24-3 while Jones, who has now lost his last three fights, fell to 49-4.
Tarver said: "The guy had great resilience. He came to regain his throne. It didn't happen tonight. I did what I came in to do."
Jones said: "You might see me back, I don't know. I just don't feel I had the urge. I still had the skills. But I'm a long way from who I was."
While no major world title was at stake, the fight attracted a sell-out crowd of more than 21,000 to the Forum Arena.
And Jones started brightly, showing his old speed to evade Tarver's blows and showing some intent in the fifth with some hurtful flurries.
But as he began to tire, Jones was limited to single shots while Tarver built up a lead behind his jab.
And although Jones staged a big final round, Tarver had already done more than enough to win the fight.