Rafael Nadal earned his 60th victory in 61 matches at the French Open, beating Robby Ginepri of the United States 6-0, 6-3, 6-0.
Nadal has won eight titles at Roland Garros, with his lone loss at the tournament coming in the fourth round in 2009. If he wins this year, he will become the first man to win five straight at the clay-court major.
Nadal played his opening match on Court Suzanne Lenglen, the second biggest stadium at the French Open.
Djokovic sails through
Novak Djokovic made light work of Portuguese Joao Sousa to reach the second round of the French Open with a 6-1 6-2 6-4 win.
The Serbian second seed clinked bottles with a ball boy he had invited to sit on his chair as the umpire was pondering whether to halt play again as light rain fell on Philippe Chatrier court.
The match had been first interrupted by rain when Djokovic, looking to win the only grand slam title missing from his collection, was 4-1 up in the first set.
It did not derail Djokovic, who barely blinked when he conceded a late break and hit 37 winners to set up a meeting with local favourite Jeremy Chardy.
Sharapova on song
Maria Sharapova took advantage of a break in the rain to win her opening match at the French Open.
The 2012 champion was first on court in the main stadium at Roland Garros, and needed little more than an hour to reach the second round by beating Ksenia Pervak 6-1, 6-2.
The match started about 1 hour, 20 minutes late because of the wet weather.
The forecast calls for more rain Monday, and for the rest of the week.
Sharapova, the seventh seed, completed a career Grand Slam at Roland Garros two years ago. She also lost to Serena Williams in the 2013 final.
Later today, eight-time champion Rafael Nadal, second-seeded Novak Djokovic and Australian Open champion Stan Wawrinka are scheduled to play.