Rafael Nadal began his campaign for an 11th French Open title with a rain-delayed 6-4 6-3 7-6 (11-9) win over Italy’s Simone Bolelli.
Resuming 3-0 down in the third set, Nadal swiftly recovered the break but was pushed hard by the world number 129.
The Spaniard saved three set points from 6-3 down in the tie-break before prevailing in damp conditions.
Nadal will play Argentina’s Guido Pella in the second round.
Argentina’s Juan Martin del Potro started slowly before overcoming French wildcard Nicolas Mahut, beating the world number 116 1-6 6-1 6-2 6-4.
Elsewhere third-seeded Croat Marin Cilic, who has reached the final of two of the past three Grand Slams, saw off Australia’s James Duckworth 6-3 7-5 7-6 (7-4).
American ninth seed John Isner hit 28 aces as he overcame compatriot Noah Rubin via two tie-breaks, 6-3 7-6 (9-7) 7-6 (9-7) while US Open runner-up Kevin Anderson also had a straight-set win, beating Italy’s Paolo Lorenzi.
Nadal, who will match Margaret Court’s all-time record for most singles titles at the same Grand Slam event if he lifts the title again, won the 2017 crown without dropping a set.
He frequently looked unsettled by Bolelli’s bold baseline hitting and claimed afterwards that the surface was different to what he was used to at a venue where he has won 80 of his 82 matches.
“The court is more slippery than usual and I slid a lot when I started off or when I moved to another side, and it was quite complicated,” he said.
“You can see that there are many more whiter zones than other years, because there are little pebbles underneath, and that’s why you don’t have the proper grip on the court.”