STORY: The African National Congress appears set to lose a parliamentary majority it has held for 30 years.
By the early hours of Friday, its vote share stood at less than 43%, with half of all polling stations having reported results.
The party of Nelson Mandela still looked likely to remain the largest political force.
But for the first time in the country's post-apartheid history, it appears set to be pushed into a coalition with other parties.
ANC chairperson Gwede Mantashe remained hopeful, however:
"We are waiting for the results. We want to win with a majority. A coalition is not our plan; it is a consequence. We will deal with that consequence when it happens."
Which party the ANC might choose to work with remains unclear.
The pro-business Democratic Alliance was in second place, with over 23%, while the new party of former president Jacob Zuma was third at around 10%.
Susan Booysen is a political analyst.
"We are already pretty sure that the ANC is going to stabilize its support levels around 42 percent of the national vote, and that is quite a significant drop from about 57 and a half percent in the national elections five years ago. So, that is a significant drop."
The last decade has seen the ANC wracked by repeated corruption scandals.
Meanwhile, South Africans have watched the economy stagnate, unemployment and poverty climb and infrastructure crumble, leading to regular power outages.
Under South Africa's proportional voting system, parties' shares of the vote determine the number of seats they get in the National Assembly, which then elects the next president.
That could still be the ANC's leader and incumbent President Cyril Ramaphosa.
However, an embarrassing showing at the polls could fuel a leadership challenge.
The electoral commission has seven days to declare full results by law, though it is usually faster than that.
