The retired tennis star, 42, shares Adira, 9 months, and Olympia, 6½ with her husband Alexis Ohanian, 41

Serena Williams is striving to be the No. 1 mom.

While chatting with PEOPLE at the Tribeca Film Festival about the premiere of her new docuseries In the Arena: Serena Williams on Thursday, June 13, the retired tennis star, 42, also caught up about life as a mom of two.

Asked how the athlete is able to satisfy her competitive craving as a mom — Williams shares daughters Adira, 9 months, and Olympia, 6½, with husband Alexis Ohanian, 41 — the mom of two shared that she turns to her kids.

“You don’t and I can’t. I have to be the best mom,” she tells PEOPLE. “I have to go to all of Olympia’s things at her school. I literally show up.”

Williams says she also looks to her beauty brand Wyn to keep her motivated.

“I started my beauty brand Wyn, which is an active beauty, which I think is super competitive itself. And so I do a lot of that and I have Serena fixtures,” she says. “So yeah, I invest in women. I invest in people of Color and that is very competitive.”

In May, Ohanian spoke to PEOPLE about the launch of his new podcast Business Dad, opening up about reveling in life as a father of two since welcoming daughter Adira last summer.

“Shout out to the mother of my children. My wife, Serena, is Super Mom,” he says of their experience as a family of four.

The father of two is excited to see his younger daughter start to get her footing, noting it’s “fun because she’s getting more mobile.”

“She’s able to have a lot more fun with her sister in terms of playing. You can already see the interactions between them. It’s a big age gap, and Olympia has a little bit of that maternal spirit. She’s like, ‘This is my 𝚋𝚊𝚋𝚢,’ and it’s great to see them together,” Ohanian shared.

“They play and sort wrestle and all that. We’re very lucky because Adira’s got a great personality and Olympia does too, plus she’s so excited to be a big sis. So seeing the two of them interact with each other has been a special kind of fun. Adira’s getting more mobile and ore vocal, and it’s only going to get even more fun.”

He joked, “I guess at some point they’re going to fight over things, but for now, let me live in bliss.”