Roger Federer marked his Italian Open return with victory against Portugal's Joao Sousa as eight-time champion Rafael Nadal also progressed in Rome.
Making his first appearance since 2016, Swiss four-time finalist Federer, 37, beat Sousa 6-4 6-3 in one hour 21 minutes to reach the third round.
Spain's defending champion Nadal, 32, took one hour eight minutes to beat France's Jeremy Chardy 6-0 6-1.
Federer plays Borna Coric next, while Nadal faces Nikoloz Basilashvili.
Both matches will be played later on Thursday after rain washed out Wednesday's play.
Australia's Nick Kyrgios forfeited his match against Casper Ruud after smashing a racquet, throwing a chair across the court and walking off court.
World number one Novak Djokovic from Serbia beat 20-year-old Denis Shapovalov 6-1 6-3, while Greece's Stefanos Tsitsipas - beaten by Djokovic in the Madrid Open final on Sunday - defeated Jannik Sinner 6-3 6-2.
Barcelona Open champion Dominic Thiem lost 4-6 6-4 7-5 to world number 38 Fernando Verdasco.
Germany's world number 51 Jan-Lennard Struff beat ninth seed Marin Cilic 6-2 6-3 to set up a meeting with Japan's Kei Nishikori, who beat Taylor Fritz 6-2 6-4.
Argentine Juan Martin del Potro will face Norwegian Ruud after beating David Goffin 6-4 6-2.
Ruud led 6-3 6-7 (5-7) 2-1 when Kyrgios forfeited the match.