Elena Rybakina beat Qinwen Zheng to reach the US Open semi-finals and displace Aryna Sabalenka at the top of the world rankings.

Frances Tiafoe came back from two sets down and 3-0 in the decider to beat Alex Michelsen in five sets, reaching a third US Open semi-final.

Ben Shelton beat defending champion Carlos Alcaraz in five sets to reach the US Open semi-finals, in the latest-finishing match in the tournament's history.

Aryna Sabalenka came through two tie-breaks to beat Linda Noskova and keep her bid for a third consecutive US Open title alive, though her world No. 1 ranking remains under threat.

Qualifier Zheng Qinwen trailed 5-0 in the opening set before beating Iga Swiatek 7-5, 6-3 to reach the US Open quarter-finals, the second match running she has recovered from that deficit.

Both defending champions advanced in straight sets at the US Open, while Frances Tiafoe knocked out seventh seed Daniil Medvedev to extend his perfect record on Louis Armstrong Stadium.

Carlos Alcaraz beat Roman Safiullin 6-4, 6-4, 6-4 in his first singles match since April, showing no problems with the wrist injury that kept him out of two Grand Slams.

An ailing Novak Djokovic lost his opening match at the US Open to Argentina's Mariano Navone, his first defeat in the first round at Flushing Meadows and his earliest Grand Slam exit in two decades.

Carlos Alcaraz plays his first singles match in four months and Aryna Sabalenka begins a bid for a third straight US Open title as both defending champions open their campaigns.

Carlos Alcaraz will return at the US Open to defend his title, ending a four-month absence with a right wrist injury that cost him the French Open and Wimbledon.