The DA was leading the ANC in Johannesburg, according to IEC results available after midday on Thursday, with just over a quarter of the city’s votes counted.
The DA was ahead in the city with 43.34% of the vote, followed by the ANC (41.17%) and the EFF (9.75%).
These were the results with 28% of the total votes tallied.
Johannesburg, Nelson Mandela Bay and Tshwane are among the hotly-contested metropolitan areas in this year’s local government elections.
News24 elections analyst Dawie Scholtz told News24 it was unlikely that any political party could secure more than 50% of the vote in Johannesburg.
"The question is: Who is going to be the biggest party - it's probably going to be the ANC by the looks of the numbers,” Scholtz said.
"The question is whether DA plus EFF will reach 50%. I think that will be very tight. My feeling at this point is that it's going to be about 45% ANC, 40% DA, 10% EFF.”
A key factor driving this year’s race in Johannesburg was the turnout of DA voters.
"In townships in Joburg, the turnout is around 55% and suburbs it's looking at about 66%.”
The higher turnout in the suburbs would help the DA a lot, Scholtz said.
In 2011, the difference was 10 percentage points, and in 2014 it was six percentage points.