Heartbreak intruded on the opening day of the soccer World Cup when Nelson Mandela's 13-year-old great-granddaughter Zenani was killed in an auto accident early on Friday.

The former South African president Nelson Mandela hugged his great granddaughter Zenani Mandela, in this 2008 photo.

After learning of the death, Mr. Mandela canceled a much-heralded appearance at the stadium where the opening match was played. He had been instrumental in attracting the month-long tournament, which has been depicted as a triumphant showcase for his country and his continent.

Zenani Mandela was returning home from the event's kickoff concert in Soweto on Thursday night, an extravaganza with stars like Alicia Keys and Shakira that was meant to launch the contest on a joyous note. At its conclusion, the sky lit up with fireworks as happy attendees made way to their parked vehicles.

According to the police, Zenani died in a one-car accident on a Johannesburg highway. The man behind the wheel, who has yet to be named, was accused of drunk driving and may also be charged with culpable homicide, the police said.

The World Cup is being played in Africa for the first time, and the presence of Mr. Mandela, the frail, 91-year-old liberation hero, was expected to be an emotional highpoint to one of South Africa's proudest days.

In ceremonies just prior to the opening match, which ended in a 1-1 tie between South Africa and Mexico, President Jacob Zuma told the crowd that the tragedy had prevented Mr. Mandela's from attending, "but he said, ‘The game must start, you must enjoy the game.' "

Details of the accident were incomplete. The Associated Press quoted a police spokeswoman, Edna Mamonyane, saying the driver was found to be drunk: "He lost control of the vehicle and it collided with a barricade."

The Mandelas might rightly be considered the nation's first family. Mr. Mandela's triumphs are well known to his countrymen, and so are his tragedies. His oldest child, Thembikele, died in a car accident in 1969. His second child, Makaziwe, died after living only nine months. His third child, Makgatho, died of an AIDS-related illness.

Zenani was one of Mr. Mandela's nine great-grandchildren. She was the grandchild of Zindzi Mandela, the elder of two daughters born to Mr. Mandela and his second wife, Winnie Madizikizela-Mandela.

The couple divorced in 1996, ending a 38-year marriage that endured the persecution of apartheid and the separation caused by his 27 years in prison. In 1998, he married Graça Machel, the widow of the Mozambican leader, Samora Machel.

The cancellation of his appearance offered a sharp counterpoint to Mr. Mandela's earlier and more vigorous years when, in a bold gesture as president, he saluted South Africa's victorious team at the rugby World Cup in 1995, urging his countrymen - black and white - to support a squad associated by many black people with the Afrikaner elite of the apartheid years.