Lindsay Davenport reached round two of the French Open with an unconvincing display against Katarina Srebotnik.
The top seed dropped serve three times as she lost the opening set but finally found her range midway through the second and went on to win 3-6 6-2 6-2.
Meanwhile, US compatriot Venus Williams eased past Spaniard Marta Marrero 6-3 6-2 at Roland Garros in Paris.
And Kim Clijsters overcame her injury worries with a confident performance as she thrashed Melien Tu 6-1 6-0.
Fourth seed Elena Dementieva and Daniela Hantuchova, the 20th seed, were other early winners.
Dementieva saw off Barbora Strycova of the Czech Republic 6-3 6-3, while Hantuchova beat Michaella Krajicek 6-3 6-1.
Davenport admitted she had been far from at her best against Srebotnik.
"I just wasn't ready to go in that first set," said the American, who has never been past the semi-finals in Paris.
"I was able to find my way in from the middle of the second set and to turn it around before it was too late."
Clijsters, who was a doubt before the event, played with a heavily strapped knee but still had too much for American Tu.
"I felt pretty good out there," said the 14th seed. "I had to test (the knee) out but it was good to have a match like this in the first round.
"I haven't had the perfect preparation but something like this definitely helps to get the rhythm back and get your mind ready for all these matches."