This is a joyous time for Serena Williams, who is expecting her first child with her fiancé, Reddit founder Alexis Ohanian. Following her pregnancy announcement on Snapchat last week, she has embraced her new role as mom-to-be on social media, from her stunning babymoon to the beautiful note she wrote to her unborn baby.

Hours after she posted that note on Monday, she composed another one — this one in response to a remark apparently made by another star in the tennis world. Ilie Nastase, the 70-year-old former top-ranked men’s player, reportedly was heard at a press conference last week making a comment about Williams’ child, saying in Romanian, "Let's see what color it has. Chocolate with milk?"

Trending stories,celebrity news and all the best of TODAY. This site is protected by recaptcha

Williams, whose fiancé is white, wrote on Instagram Monday afternoon, “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.”

She continued that the “world has come so far,” but it still has “so much further to go. Yes, we have broken down so many barriers — however, there are a plethora more to go.

“This or anything else will not stop me from pouring love, light and positivity into everything I do. I will continue to take a lead and stand up for what’s right.”

Williams quoted the Maya Angelou poem “Still I Rise,” which includes the lines, “You may shoot me with your words ... you may kill me with your hatefulness, but still, like air, I’ll rise.”

RELATED: Read Serena Williams' touching letter to her baby: 'I can't wait to meet you'

The message came one day after the International Tennis Federation issued a provisional suspension of Nastase. The ITF had previously announced it was investigating Nastase for his “unacceptable behavior” as Romania’s Fed Cup captain during a tennis match over the weekend, as well as for “previous comments” he’d made earlier in the week.