Novak Djokovic was made to work hard before overcoming Brazilian Rogerio Dutra Silva on Philippe-Chatrier.
Persistent rain has forced the suspension of play on Day 2 at Roland-Garros, bringing an end to Monday's first-round action.
Rafael Nadal, the 10-time champion, was one of the players whose match with Simone Bolleli will now be completed tomorrow. Two-time former champion Maria Sharapova will now open her campaign against RIchel Hogenkamp on Tuesday.
Rafael NADAL vs Simone BOLELLI: Nadal leads 6-4 6-3 0-3
John ISNER vs Noah RUBIN: Isner leads 6-3 7-6(7)
Horacio ZEBALLOS vs Yuichi SUGITA: Zeballos leads 6-4 6-6(2-0)
Matt EBDEN vs Thomas FABBIANO: Tied 4-6 7-5 2-6 6-3
Joao SOUSA vs Guido PELLA: Pella leads 6-2 6-3 2-3
Varvara LEPCHENKO vs Elise MERTENS: Mertens leads 6-7(9) 7-6(4) 3-0