Novak Djokovic began his campaign for a fourth successive grand slam title with victory over Italy's Potito Starace at the French Open.
The Serbian eventually prevailed 7-6 (7-3) 6-3 6-1 after being given a workout in the opening set from the claycourt specialist.
The world number one already holds the Wimbledon, US Open and Australian Open trophies and is looking to add the one title he has never won.
For a set and a half Djokovic looked far from a potential champion, the top seed cutting a frustrated figure as world number 97 Starace kept pace with him.
Djokovic could not take two set points in the 12th game of the opener but he won the tie-break easily enough and finally broke through in the fifth game of the second set.
From there he looked more like the player who has dominated the sport for 18 months, moving well and allowing a weary-looking Starace only two more games.
In the second round Djokovic will play Slovenia's Blaz Kavcic, who put out former world number one Lleyton Hewitt in four sets.
Djokovic is bidding to become only the second player in the Open era - and third in all - to hold all four grand slam titles at the same time.
"Potito is a specialist on this surface but I played well considering it was the first match at this year's Roland Garros," said Djokovic, who won rousing applause for conducting his on-court interview in French.
"I hope to go on and get good results, but it's too early to talk about the final."
In other results, seventh seed Tomas Berdych, a dark horse for the title, began his campaign with a straightforward 6-3 6-4 6-1 victory over Dudi Sela.
Fellow big hitter Milos Raonic, seeded 19, was equally impressive in seeing off Ruben Ramirez Hidalgo 6-4 6-2 6-2.