Muhammad Ali's championship belt from the Rumble in the Jungle - his 1974 heavyweight title bout with George Foreman - was sold at auction on Sunday for $6.18million.

The belt, won by the legendary boxer after he stopped his rival with an eighth round knockout in Zaire, was purchased by Indianapolis Colts owner Jim Irsay.

The 63-year-old has already purchased a large assortment of pop culture memorabilia, the Isray Collection, which he intends to tour across the nation.

"Proud to be the steward!" Isray tweeted, while revealing the belt would be on display next month in Chicago and then in Indianapolis in September.

Ali's belt falls short of becoming the most expensive piece of sporting memorabilia to be sold at auction.

Diego Maradona's iconic Hand of God shirt - worn during Argentina's quarter-final victory over England at the 1986 FIFA World Cup - fetched just over £7.1m ($8.9m) in May.