Muhammad Ali's championship belt from his 1974 Rumble in the Jungle heavyweight title fight against George Foreman has sold at auction for $US6.18 million ($8.93 million).
The winner of the heated competition for the belt was NFL team owner Jim Irsay, Dallas-based Heritage Auctions confirmed.
Irsay, who owns the Indianapolis Colts, confirmed he had acquired the belt for his collection of rock music, American history and pop culture memorabilia that is currently touring the United States.
"Proud to be the steward!" Irsay tweeted.
Heritage's director of sport auctions Chris Ivy said Irsay had competed with another bidder for several hours before emerging victorious with the prized piece of memorabilia.
The 1974 fight pitting Ali against the fearsome Foreman in the African nation of Zaire was one of boxing's most memorable contests
Ali won the fight by knockout in the eighth round.
AP/ABC