Serena Williams was given a stern examination by Swiss youngster Stefanie Voegele in the opening round of the French Open yesterday.
The top seed, who is looking for her second Roland Garros crown after winning the title for the only time in 2002, has struggled with injury since clinching the Australian Open in January.
And Williams certainly did not have things all her own way on Philippe Chatrier yesterday, particularly in the first set, but she did enough to come through 7-6 6-2.
Voegele, 20, was the better player for much of the opening set but it was the world number one who stepped up her game when it mattered in the tie-break.
The second set began in the same fashion but Williams forged ahead with successive breaks before serving out the victory.
Williams will face Germany's Julia Goerges in the second round.
Third seed Caroline Wozniacki had no such problems dispatching of Alla Kudryavtseva to reach round two, where she will play Tathiana Garbin.
Wozniacki showed no sign of the ankle injury that forced her to retire from the quarter-finals of the Warsaw Open last week in winning 6-0 6-3.
Fourth seed Jelena Jankovic defeated Alicia Molik 6-0 6-4 in one of the last matches to finish.
Jankovic said: “I'm happy not to play in the sun but on the other hand I was waiting almost the whole day to play my match.”
Fifth seed Elena Dementieva made light work of Petra Martic, winning 6-1 6-1, while Na Li, the 11th seed, had a little more trouble seeing off home favourite Kristina Mladenovic 7-5 6-3.
Seventh seed Samantha Stosur had a difficult first set against Simona Halep but the Australian accelerated to win 7-5 6-1.