Answer
Leylah Fernandez defeated Naomi Osaka 5–7, 7–6(2), 6–4 in the third round of the 2021 US Open. It was a major upset, as Osaka was the defending champion and ranked No. 3 in the world at the time. Fernandez, who was ranked No. 73 in the world at the time, went on to reach the final of the tournament, where she lost to Emma Raducanu.