Serena Williams, Sloane Stephens try to reach semifinals at US Open

NEW YORK — Serena Williams and Sloane Stephens can give the United States two U.S. Open semifinalists, a year after an all-American women’s final four.

And for the first time since 2006, the host country can have a man there, too.

Williams and Stephens first have to win quarterfinal matches Tuesday. Defending champion Stephens is up first on Arthur Ashe Stadium, facing No. 19 seed Anastasija Sevastova in a rematch of Stephens’ three-set victory in the same round at Flushing Meadows last year.

Williams, seeded 17th, meets the last player to beat her at the U.S. Open. Karolina Pliskova, the No. 8 seed, knocked off Williams in the 2016 semifinals before the 23-time Grand Slam champion missed last year’s tournament, when she gave birth.

On the men’s side, defending champion Rafael Nadal faces Dominic Thiem at night in a rematch of Nadal’s French Open victory, and 2009 U.S. Open champion Juan Martin del Potro plays John Isner in the other quarterfinal.

If Isner wins, he would be the first American in the U.S. Open semifinals since Andy Roddick in 2006.