Defending champions Aryna Sabalenka and Carlos Alcaraz look to reach the US Open quarterfinals

NEW YORK (AP) — Aryna Sabalenka and Carlos Alcaraz look to take another step toward defending their U.S. Open championships when they play Sunday for spots in the quarterfinals.

The top-ranked Sabalenka leads off against Taylor Townsend at Arthur Ashe Stadium in their first career meeting. Alcaraz, seeded second behind Alexander Zverev and playing his first tournament back following a wrist injury , follows against No. 20 Tommy Paul.

Townsend and Paul are among the 10 Americans to reach the men’s and women’s round of 16. That is the most in the fourth round at any Grand Slam in nearly a quarter-century, dating to the 2002 U.S. Open, when there were 11.

The five U.S. men — Paul, Ben Shelton, Learner Tien, Frances Tiafoe and Alex Michelsen — are the most at a major since eight in 1995 at Flushing Meadows.

Shelton, the No. 8 seed, faces Stefanos Tsitsipas on Sunday night at Ashe, followed by fellow American Emma Navarro against Anna Kalinskaya. Other fourth-round matches include Jessica Pegula versus Sorana Cirstea, Tiafoe versus Daniil Medvedev and Wimbledon champion Linda Noskova versus Marta Kostyuk.

Tien played into early Sunday to beat Jakub Mensik in a five-set gem between a pair of emerging stars. At 20, Tien is the youngest American man in the U.S. Open fourth round since Andy Roddick in 2002.

See AP’s full tennis coverage here