Williams, who announced she was pregnant last Wednesday, posted a lengthy statement on her Instagram account explaining her disappointment with Nastase.
Upon learning of Williams' pregnancy, Nastase said, "Let's see what color it has. Chocolate with milk?"
Williams responded, "It disappoints me to know we live in a society where people like Ilie Nastase can make such racist comments towards myself and unborn child, and sexist comments against my peers.
"I have said it once and I'll say it again, this world has come so far but yet we have so much further to go. This or anything else will not stop me from pouring love, light and positivity into everything that I do. I will continue to take a lead and stand up for what's right."
Williams closed her statement by saying she is "not afraid unlike (Nastase)" and thanked the International Tennis Federation for their consideration of the facts in this case while pledging her support.
In response to Williams' statement, Nastase told the Associated Press he considers Williams to be his friend and added, "I want to know, what word I used is racist?"
Konta was left in tears and their match was suspended.
Despite being barred from the premises, Nastase attempted to enter the arena when the match resumed on Sunday but was not allowed in.
Earlier this month, Nastase made claims that the 35-year-old Williams, a 23-time Grand Slam champion and the No. 1 player in the WTA Rankings, used performance-enhancing substances. His claims were unsubstantiated.