Mandela's moment of triumph turned into tragedy on the eve of the games he helped bring to his country when his great-granddaughter was killed in a car crash leaving a World Cup concert.
Zenani Mandela, who turned 13 on Wednesday, was the only person to die or to be injured in the one-car accident in the township of Soweto. Police declined to release details of the crash.
Mandela, who led the fight against apartheid and is considered the father of the new South Africa, is now a frail 91. But he had been expected to make an appearance at the opening ceremony of the games today.
The Nelson Mandela Foundation issued a statement announcing Zenani's death and said the Mandela family was in mourning and that it would be "inappropriate" for him to attend the ceremony.
"We are sure that South Africans and people all over the world will stand in solidarity with Mr. Mandela and his family in the aftermath of this tragedy... Madiba will be there with you in spirit today," the statement said, using the honorary title for a tribal elder that has become Mandela's respectful nickname.
It added, "The family has asked for privacy as they mourn this tragedy."
Before the tragedy, Mandela was enjoying the run-up to the games, meeting this week with the Black Eyed Peas and players from several of the competing teams.
Mandela's use of sports to unite his country was depicted in the recent movie "Invictus" in which he used an international rugby competition to heal racial divisions shortly after apartheid was abolished.
Mandela was instrumental in bringing this month's games to South Africa, making it Africa's first ever World Cup.
Mandela changed South Africa when he was elected its first black president in 1994, bringing to an end the brutal system of racial segregation there.
Now, the world is watching South Africa again for a different reason: It is the host of the biggest, most anticipated sporting event in the world.
Mandela's involvement in South Africa's bid to host the 2010 soccer tournament put his country's application on top, edging out that of Morocco. He has said sports have the power to change the world and to break down racial barriers.
"He led the process up to the very last day …," Mandela's wife, Graca Machel, said in an interview with "Good Morning America" anchor Robin Roberts in South Africa this week. "I mean, the committee was considering whether it's South Africa or it's Morocco. And then we got the call to say 'we need Madiba to come, he has to play his magic here.'"
Mandela -- whose tribal title is 'Madiba' -- answered the call. The rest is history in the making.
"This is a moment of convergence, of good will, of hope, of excitement, of exhilaration in the sense of, we as Africans feeling that we can make it happen," Machel told Roberts.
The fact that the nation that until so recently adhered to apartheid is now hosting a game that is thought to unite billions of people around the world is a singular achievement of which every South African is proud.
Apartheid was the brutal legalized system of racial segregation that favored ruling whites and marginalized South Africa's black majority. It was dismantled in the early 1990s, in large part because of efforts led by Mandela.