JOHANNESBURG - The death of Nelson Mandela's granddaughter cast a shadow over the opening day of the World Cup on Friday, dampening the spirits of a nation proud and excited to be hosting the world's most popular sporting event. Zenani Mandela, the 13-year-old great-granddaughter of the former South African President, was killed in a car accident on the way home from a World Cup concert in Soweto on Thursday night, where tens of thousands of people had sung and danced with headline music stars Shakira and the Black Eyed Peas. On Friday, streets in downtown Johannesburg were filled with cars and pedestrians waving South African flags and blowing vuvuzelas in the hours soon after dawn, as news that one of Mandela's nine great grandchildren was emerging. Heavy security was evident in Johannesburg and in Soweto, near the Soccer City Stadium where South Africa was opening the tournament on Friday afternoon with a game against Mexico. Johannesburg police spokeswoman Edna Mamonyane said the driver of the car involved in the one-car accident, a male, had been arrested and charged with drink-driving. Mamonyane said the driver, whom police would not name, could also face culpable homicide charges.