Novak Djokovic, the world number one, began his defence of his French Open championship with a straight-set victory over Yoshihito Nishioka of Japan.
Djokovic of Serbia won 6-3, 6-1, 6-0 on Court Philippe Chatrier, dropping only four games.
Djokovic was making his Grand Slam comeback after being deported from Australia just before the Australian Open in January.
Rafael Nadal, the 13-time champion, defeated Jordan Thompson 6-2 6-2 6-2 earlier in the day.
The 20-time Grand Slam champion has had a difficult season on the court, suffering shock losses in Monte Carlo and Belgrade before rallying to win his first trophy in six months at the Italian Open last week without dropping a set.
Djokovic, who might meet Nadal in the quarterfinals as he tries to match the Spaniard’s record of 21 major titles, kept up his good form from Rome, dispatching Nishioka in under two hours.
Following a low-key first set, the two-time winner ramped up the tension in the second, conceding just one game while breaking Nishioka’s serve in four games, sparking jeers from sections of the crowd at points.
Nadal started his quest for a record-extending 14th men’s title with a dominant straight-set victory over Australia’s Thompson in Monday’s day session.
The 35-year-old fifth seed won his 106th French Open match, and he will face Corentin Moutet in the second round after the Frenchman defeated 2015 champion Stan Wawrinka.
Nadal was hampered by a recurrence of a persistent foot issue earlier this month at the Italian Open, but he appeared to be moving freely against Thompson, the world number 82.
As an increasingly frustrated Thompson ran out of ideas, Nadal broke service in the first, fifth, and seventh games to take the second set.
Nadal got a break back in the third game, but Nadal’s forehand volley put him up 3-2, and he won the next three games to progress.
6-0, 6-2, while 13th seed Taylor Fritz of the United States defeated Argentina’s Santiago Rodriguez Taverna in five sets, 7-6 (7-2) 3-6 6-3 4-6 6-4.
When play was suspended due to rain delays, ten matches were still in progress. Play will resume on Tuesday.