Answer
In 2021, Maria Sakkari reached the semifinals of two Grand Slams: the French Open and the US Open. At the French Open, she defeated Aryna Sabalenka and Iga Swiatek before losing to Barbora Krejčíková in the semifinals. At the US Open, she defeated Sloane Stephens, Petra Kvitová, and Karolina Pliskova before losing to Emma Raducanu in the semifinals.