The second semifinal between defending champions Sara Errani/Andrea Vavassori and the all-American, last-minute alternate pairing of Danielle Collins/Christian Harrison is underway, as they bid to join Świątek/Ruud in the mixed doubles finale.

Italians Sara Errani and Andrea Vavassori retained their mixed doubles title at the U.S. Open on Wednesday, overcoming Iga Swiatek and Casper Ruud 6-3 5-7 10-6 in the competition's reimagined format that drew some of the top singles players.

Sara Errani and Andrea Vavassori weren't even sure they would get to defend their US Open mixed doubles title. Organizers revamped the tournament because they wanted singles superstars, not doubles specialists.