The 19-year-old lost just two games as she defeated Jelena Ostapenko 6-0, 6-2 at Arthur Ashe Stadium.
The Latvian Ostapenko, the number 20 seed, clearly messed up the women’s draw when she eliminated the defending champion and world number one Iga Swiatek in round four.
However, she was unable to capitalize on her own performance as Gauff won the first set in just 20 minutes.
Ostapenko tried harder in the second set and finally managed to hold serve in the fifth attempt.
But Gauff finished the job in one hour and eight minutes and reached the last four of her home Grand Slam tournament for the first time.
“It feels great, I’m so happy,” she said. “Last year I lost in the quarterfinals and wanted to do better. There’s still a long way to go, but I’m happy and ready to get back to work.
“To be honest, I didn’t feel comfortable the whole game, not even on match point. I know the game she’s playing. It’s really tough against them – you can’t really be aggressive. She is a top player and had a great tournament.
“There’s a saying in basketball: ‘Defense wins games.’ Things don’t always work out in tennis, but today it did.”
Gauff will face the winner of the game on Tuesday evening between Sorana Cirstea and Karolina Muchova in the semi-finals.
https://www.standard.co.uk/sport/tennis/us-open-2023-tennis-coco-gauff-jelena-ostapenko-serena-williams-b1105068.html US Open 2023: Coco Gauff beats Jelena Ostapenko, equals Serena Williams and reaches the semi-finals for the first time