Keystone
Switzerland's opponent in the quarter-finals of the United Cup is Greece.
After beating Japan, Maria Sakkari (WTA 51) and Stefanos Tsitsipas (ATP 34), both once ranked No. 3 in the world, also defeated Great Britain.
Belinda Bencic (WTA 11), who started the new year with two victories, trails Sakkari 1:2 in the head-to-head, although she had to retire in their last duel last May after losing the opening set due to an arm injury. Wawrinka and Tsitsipas have only met once before - at the French Open in June 2019, when the Frenchman won in five sets.