Former champion Emma Raducanu opened her 2025 US Open campaign by sweeping past Japanese qualifier Ena Shibahara 6–1, 6–2, her first victory at Flushing Meadows since claiming the title as an 18-year-old in 2021. The Briton, now working with coach Francisco Roig, produced just four unforced errors and saved the only break point she faced, marking her 25th match win of the season. Raducanu will meet Indonesian qualifier Janice Tjen in the second round. Top seed Aryna Sabalenka began her title defence with a 7–5, 6–1 defeat of Spain’s Rebeka Masarova. The world No. 1 needs to reach at least the quarter-finals to guarantee she retains her ranking ahead of Poland’s Iga Świątek and will next face Russia’s Polina Kudermetova. Two-time champion Naomi Osaka also advanced, dispatching Belgium’s Greet Minnen 6–3, 6–4 in her first match at the tournament since reaching the Montreal final earlier this month. The Japanese star, seeded 23rd, converted all six break-point chances to book a second-round meeting with American Hailey Baptiste.