Andre Ward has claimed the IBF, WBA and WBO light-heavyweight titles after surviving an early knockdown to beat Sergey Kovalev on points.
The American held on to his unbeaten record courtesy of a unanimous decision, with all three judges at the T-Mobile Arena in Las Vegas scoring 114-113 in his favour.
Kovalev made the faster start and left his opponent on the canvas in the second round by a stinging right-hander, only the second time that Ward had been floored in his career.
The 32-year-old beat the count but went on to struggle against his opponent until the seventh round, when he landed a good left which jolted Kovalev.
Ward subsequently won all of the last six rounds on two scorecards, and five of six on a third, to inflict the Russian's first defeat in 32 fights.
The result means that Ward becomes only the seventh fighter to win titles at super middleweight and light heavyweight, a class that includes Sugar Ray Leonard, Thomas Hearns, Iran Barkley and Roy Jones Jr.