Earlier, Denis Shapovalov and Andrey Rublev had cruised into the second round with emphatic straight-sets victories.
Canadian 12th seed Shapovalov, who reached the US Open quarter-finals last week, shook off jetlag to beat Guido Pella 6-2, 6-3, firing seven aces and 23 winners past the Argentine.
Ninth seed Rublev, making his debut at the Foro Italico, beat qualifier Facundo Bagnis 6-4, 6-4 to book a spot in the second round where he will face Hubert Hurkacz.
Alex de Minaur, another quarter-finalist at Flushing Meadows, was knocked out by Dominik Koepfer with the German fighting back from a set down to win 3-6, 6-3, 7-6 (7-5).
In the women’s draw, Angelique Kerber was knocked out in a 6-3, 6-1 defeat to Czech Katerina Siniakova while Coco Gauf won her first ever match on clay.
Kerber, who reached the last 16 at the US Open, lasted only 69 minutes on the clay as Siniakova advanced in straight sets with five breaks of serve.
Kerber was almost bageled in the second set before she saved three match points to break for the first time in the contest but Siniakova broke back in the next game to seal victory.
American teenager Gauff, playing in her first ever main draw match on clay, came back from 4-2 down in the opening set to beat Tunisian Ons Jabeur 6-4, 6-3.