Joe Calzaghe put on one of his finest displays to dismantle Roy Jones Jr at Madison Square Garden in New York in the early hours of Sunday morning.
Calzaghe was floored in the first round by a Jones right hand but thereafter assumed full control of the fight.
The Welshman opened a big cut over Jones' left eye in round seven and the 39-year-old was clinging on in the end.
All three judges scored the bout 118-109 in Calzaghes favour.
The Newbridge fighter extends his unbeaten record to 46 fights while four-weight world champion Jones, of Pensacola, Florida, falls to 52 wins and five defeats and may now choose to retire.
Calzaghe was cheered on by an estimated 7,000 British fans out of a crowd of 14,000, including Lennox Lewis and former foes Bernard Hopkins and Mikkel Kessler, both hoping to lure the Welshman into continuing his career.