Third seed Rafael Nadal began his bid for a 21st Grand Slam men's singles title with a straight-set win against Australia's Alexei Popyrin.
The 34-year-old Spaniard, going for a record-extending 14th triumph at Roland Garros, won 6-3 6-2 7-6 (7-3).
After easing through the first two sets, Nadal fought off two set points at 5-2 in the third before recovering.
Russian seventh seed Andrey Rublev is out after losing in five sets to German world number 42 Jan-Lennard Struff.
Rublev's defeat means there is one fewer obstacle for Nadal in his side of the draw as the Spaniard seeks to set an outright record for major men's singles titles - a record he shares with Roger Federer at present.