Tell me about the 2018 U.S. Open.

- It was a lot of mixed, mixed emotions, yeah.

- I remember sitting in my bedroom, oh, gosh, just to see you and Serena battle it out, and I just felt for both of you at that moment.

Oh, you brought me to tears, because you were so grateful, you know?

And I know that she was like, a role model and, you know, and, and so-- could you just share a little bit of that moment?

- It felt like a dream to me to be playing against her because I did like, a report on her, maybe fourth grade or something, and I was just like, if I ever managed to get to the finals of a Slam, I would love to play Serena.

Um, and then it actually happened.

So it was definitely a really surreal feeling.

(tense music) (crowd cheering) I always thought about what would happen if I won a Slam, but just everything that occurred was outside of my imagination.

I wasn't really prepared for it.

There was a lot of people saying that I didn't like, deserve to win, or that win didn't count, but it also really brought my ambitions very high.

Like, that just motivated me a lot to win like, the Australian Open right after that.

So, but, yeah, I just remember feeling in that moment very happy to have won.

But also I felt very sad because I knew how much it meant to her.

- [Billie] Naomi's 2018 U.S. Open win against her childhood hero, Serena Williams, was an historic night in tennis, and Naomi's first Grand Slam win.

At the awards ceremony, the stadium erupted in boos.

It was an emotional, intense moment, as Naomi hid behind her visor.

Serena stepped in closer and placed her arm around Naomi's shoulder in a sign of solidarity.

It was one of the most powerful illustrations of support that I've ever seen in our sport.

- In your space, in tennis, how were you able to really adapt and adjust?

- I think, for me, it's just more about being grateful.

I have to always pat myself on the back, like, even if I feel like other people don't, what's most important is how I feel on the inside.

- When I was competing, if I talked about my mental health, I was considered weak.

- Mm-hmm.

- But for you to open that door for so many people that didn't even know they could have that conversation... - [Billie] In 2021, Naomi caused quite a stir when she decided not to interact with the media, and decided to focus on her mental health instead.

After skipping the first press conference following her opening round win, organizers fined her and threatened to suspend her from the tournament and all other Grand Slams that year.

Naomi shocked the world and pulled out altogether, and revealed that she had been struggling with depression and anxiety for years, becoming one of the first international sports stars to raise awareness and talk about her mental health struggles publicly.

- In the beginning, I remember feeling a bit ashamed about it because there is always that stigma of, like, you are weak if you talk about it, and you're giving your opponents like, a... like, an edge or something?

Um, but then I think I realized, and just interacting with other athletes, and them saying that me talking about it helped them out a lot, it's when I realized, like, I'm not the only one that feels this way.

- Right.

- And it's better for everyone to just talk about it 'cause then it'll become more, I don't want to say normal, but less stigmatized.