US Open 2026: Serena Williams and Carlos Alcaraz’s star-studded US Open mixed doubles run ended in the quarter-finals after Belinda Bencic and Flavio Cobolli defeated the pair. The duo reached quarter-finals of the US Open mixed doubles before being beaten by fourth seeds Belinda Bencic and Flavio Cobolli. while Novak Djokovic and Aryna Sabalenka suffered a shock first-round exit.