Top-ranked defending US Open men's champion Jannik Sinner swatted aside Czech Vit Kopriva 6-1 6-1 6-2 in his tournament opener.
The Italian, who had entered last year's tournament under the dark cloud of a doping controversy after escaping a ban despite failing two drug tests, enjoyed strong crowd support as he set up a second-round meeting with Australian Alexei Popyrin.
10th seed Lorenzo Musetti outlasted big-serving Frenchman Giovanni Mpetshi Perricard 6-7(3) 6-3 6-4 6-4 at the Louis Armstrong Stadium and will face Belgian David Goffin.
After Daniil Medvedev's chaotic exit on Sunday, Marin Cilic became the latest former champion to be knocked out as 23rd seed Alexander Bublik beat the Croat 6-4 6-1 6-4 on Grandstand, while 14th seed Tommy Paul made short work of Denmark's Elmer Moller 6-3 6-3 6-1 to book a second-round clash with Portugal's Nuno Borges.
Third seed Alexander Zverev closed out the evening's action on the main showcourt by beating Chile's Alejandro Tabilo 6-2 7-6(4) 6-4 to set up a meeting with Scotland's Jacob Fearnley, who overcame serving 18 double faults in a 7-5 6-2 5-7 6-4 victory over Roberto Bautista Agut.
