Serena Williams and Daughter Olympia Wear Matching Outfits at U.S. Open

Serena Williams' daughter, Olympia, matched her mom's fashion choices at the U.S. Open on August 29.

The 4-year-old, whose full name is Alexis Olympia Ohanian Jr., wore a black Nike dress bedazzled with rhinestones, which mimicked the ensemble Williams played in.

The tot's hair was also a tribute to the 23-time Grand Slam champion, with white beads adorning the bottom of Olympia's braids. This was the hairstyle that Williams wore in 1999 when she won her first U.S. Open.

Serena Williams Daughter Olympia Matching U.S. Open
Serena Williams celebrates after defeating Danka Kovinić of Montenegro during the Women's Singles First Round on Day One of the 2022 U.S. Open on August 29, 2022 in New York City. (Inset) Alexis Olympia Ohanian Jr. looks on during the match. The tennis champion and her daughter wore matching outfits to the tournament. Al Bello/Getty Images 2/Getty Images

This week, the tennis champion began what would likely be her last U.S. Open. The 40-year-old announced her retirement from the sport in an essay published by Vogue.

"I have never liked the word retirement. It doesn't feel like a modern word to me," Williams told the magazine in an article published on August 9.

"I've been thinking of this as a transition, but I want to be sensitive about how I use that word, which means something very specific and important to a community of people.

"Maybe the best word to describe what I'm up to is evolution," Williams said. "I'm here to tell you that I'm evolving away from tennis, toward other things that are important to me."

The Michigan native started Serena Ventures, a venture-capital firm, in 2014 and she plans to expand her family with her husband, Reddit co-founder, Alexis Ohanian.

"I've been reluctant to admit to myself or anyone else that I have to move on from playing tennis," Williams added, noting it's "like a taboo topic" in their household.

"I can't even have this conversation with my mom and dad. It's like it's not real until you say it out loud.

"It comes up, I get an uncomfortable lump in my throat, and I start to cry," Williams said. "The only person I've really gone there with is my therapist!"

Williams defeated Montenegro's Danka Kovinić 6-3, 6-3, and will play against Estonia's Anett Kontaveit in the competition's second round on Wednesday, August 31. She also plans on playing doubles in the U.S. Open with sister Venus Williams.

Following Monday's win, Williams told journalist Gayle King that the atmosphere on the court at the USTA Billie Jean King National Tennis Center in New York City was "a lot," explaining that the crowd noise was "overwhelming."

"I feel so comfortable on this court and everyone here, I just want to do my best and that is all I can do," Williams said. "The crowd was crazy. They really helped pull me through."

Celebrities were everywhere during the first-round game to watch Williams in action, including Hugh Jackman, Bella Hadid, Vera Wang, Ashley Graham, Rebel Wilson, Anna Wintour, Gladys Knight, Lindsey Vonn, Queen Latifah, former United States President Bill Clinton and more.

Newsweek reached out to Williams' representative for comment.