In a heartfelt recollection, American tennis player Caty McNally recently shared the unforgettable experience of facing Serena Williams at the US Open, calling it one of the greatest moments of her young career.

It all began after McNally won a hard-fought first-round match against Timea Bacsinszky, a former top player herself. Shortly after, while in the locker room, McNally found herself watching the much-anticipated first-round clash between Maria Sharapova and Serena Williams. She soon realized the gravity of her situation: she would face the winner. “Serena won, and I was like, ‘I play the winner of that match,’” McNally recalled.

Preparing for the biggest match of her life, McNally got a rare chance to practice on Arthur Ashe Stadium, but she quickly learned that practicing on an empty court during the day was nothing like playing a night match under the stadium lights. “I remember walking out for the night match against her and it was really dark. The lights were off at the coin toss and it felt like we were in an NBA game or something,” she said. Once the lights came on, the massive arena was packed, creating an electric atmosphere.

Determined not to let the moment overwhelm her, McNally gave herself one simple rule: “Keep your head down and don’t look up at her because the second you do, you’re going to be like ‘holy s{expletive}, this is Serena Williams, this is insane!’”

McNally’s adrenaline and focus paid off early as she stunningly won the first set, prompting her to throw her arms up in a spontaneous moment of joy.

She laughed admitting, “I threw my arms up, I don’t even know why I threw my arms up, I think it was like pure adrenaline, and I’m like- I should not have done that, I definitely shouldn’t have done that. The part of the reason why I threw my hands up was because, the crowd was loving it and they were supporting me, which was a lot of fun to be in than just you know not play against Serena and the whole crowd. “It was an amazing experience,” she said. “I’ll be able to tell my kids one day that I won a set off Serena Williams. Not a lot of people can say that.”

It’s a memory McNally will carry forever, a symbol of her courage and a career-defining moment against an all-time legend.