The sauce was used on McJordan Burgers, named for basketball icon Michael Jordan. The promotional item was sold in limited markets for a short time in the 1990s, when Jordan led the Chicago Bulls to six NBA championships.
Mort Bank, of Bismarck, saved the gallon jug of sauce after selling his McDonald's restaurants in Bismarck-Mandan and Minot in 1996.
"It was in my basement and I would look at it occasionally," he told The Bismarck Tribune. "I thought it would be worth something someday."
Bank advertised the sauce on eBay, saying: "A once in a lifetime chance to own the rarest of rare Michael Jordan and McDonald's collectible!" It sold for $9,995 Monday night to a buyer from Chicago whom Bank has not identified.
Bank told the Chicago Tribune that the buyer was not Jordan himself. Jordan opened a steakhouse in Chicago last year.
"I'm sure he's a Bulls or Michael Jordan fan, and hopefully he's not going to put it on his ribs or his burger," Bank told KXMB-TV of the buyer. "But it's up to him; he can do whatever he wants with it."
Bank said he has at least three storage units full of McDonald's memorabilia and other collector's items that he has been selling on eBay for three years. He has sold items to buyers as far away as China, Japan, Brazil and Europe, though never for as much money as the sauce garnered.
"I'm pretty ecstatic," he told the Bismarck Tribune. "You never know what is going to be a hot item."