Despite the ugly remarks it appears Banciu won't be out of a job.
It's perhaps the most obvious example of racism Williams has been subjected to during her storied career.
Williams said she was subjected to racial slurs at Indian Wells in California in 2001, prompting her to not play in the tournament for many years.
"I remember the whole stadium was 99 per cent white people and they were all booing," Williams said later. "There were racial slurs too. It was like this echo."
In Miami in a spectator was removed from one of her matches after an outburst. "The guy said, 'Hit the net like a Negro would'," Williams said.
"I was shocked. I couldn't believe it. I had to do a double take. I think I hit a double fault at that point.
"Who says these things outside of first grade. At a professional venue you don't do that. It was shocking, I couldn't believe he would stoop to that level."
Williams fell short of equalling Margaret Court's record of 24 Grand Slam victories when she was toppled by Canadian wonder teen Bianca Andreescu in the 2019 US Open final.
The loss made it four straight Grand Slam final losses since Williams returned to the court following the birth of her daughter in 2017.