Main draw play is underway at the U.S. Open. Nineteenth-seeded Jasmine Paolini was among those playing in the opening set of matches at the Billie Jean King National Tennis Center on Sunday. Third-ranked Jessica Pegula leads off at Arthur Ashe Stadium against Elena-Gabriela Ruse at noon, followed on the men's side by Daniil Medvedev against Hugo Gaston. Novak Djokovic begins his quest for a record-extending 25th Grand Slam title on Sunday night against Mariano Navone. Venus Williams faces fellow American wild card Sophia Kenin in the last match of the night at Ashe.