Coco Gauff will start her U.S. Open title defense against Zeynep Sonmez on Tuesday night, a first-round meeting that gives the defending champion a clean path to begin and gives Sonmez the biggest stage of her career. It is their first professional meeting.
Gauff arrives as the favorite after winning the Cincinnati Open in her most recent tournament, beating Marie Bouzkova, Marta Kostyuk and Jessica Pegula on the way to the title. She also reached the semifinals at Wimbledon and the National Bank Open, and she won the U.S. Open in 2023. Sonmez, 24, has spent this season building the kind of record that makes an upset possible even when the odds do not. She has eight wins against women ranked in the top 50, including victories over Ekaterina Alexandrova and Jasmine Paolini.
That is why this opening-round match has drawn attention beyond the usual first-week schedule. Gauff has reached the fourth round at the U.S. Open in both 2024 and 2025, but she did not get any farther in either year, which leaves her chasing more than a good start. Sonmez, meanwhile, has already shown she can push beyond expectations, with third-round runs at Wimbledon and this year’s Australian Open, plus a second-round finish at last year’s U.S. Open.
The gap is still there. Gauff is expected to win, and the market reflected that with Sonmez listed at +6.5 games at +110 through FanDuel, but Sonmez has already beaten enough top-50 opponents this season to make that number feel less comfortable than it looks. If she is going to turn this into a real match, she will need to make Gauff play long points early and keep the defending champion from settling into her usual rhythm.
For Gauff, Tuesday night is the first step toward another title run. For Sonmez, it is a chance to prove that the results she has built this season belong on the same court as the player trying to defend the trophy.
