Italy’s Lorenzo Sonego, the No. 28 seed, topped China’s Yunchaokete Bu 6-1, 6-4 and Australia’s Aleksandar Vukic upset 31st-seeded Cameron Norrie of Britain 6-3, 6-7 (2), 6-3.

The mixed-doubles field at the US Open, which begins next month in New York, will be a star-studded event. The United States Tennis Association announced Tuesday the eight ...