Third seed Marat Safin made hard work of his first-round victory over Raemon Sluiter at the French Open on Tuesday.
The Russian has been in poor form recently and stumbled at a set and 3-1 up, eventually winning 6-1 4-6 6-4 6-2 to set up a clash with Lukas Dlouhy.
Eighth seed Guillermo Coria made smooth progress with a 6-4 6-2 6-4 win over Kenneth Carlsen of Denmark.
Number two seed Andy Roddick cruised past France's Jo-Wilfried Tsonga in straight sets to win 6-3 6-2 6-4.
And former champion Juan Carlos Ferrero made a confident start, beating Karol Beck 6-4 6-3 6-3.
But Brazil's former world number one and three-times champion Gustavo Kuerten was knocked out by Spaniard David Sanchez beat him 6-3 6-0 4-6 6-1.
Ninth seed Guillermo Canas humbled highly-rated French teenager Gael Monfils 6-3 6-1 6-0, and 21st seed Tommy Haas beat Florian Mayer 6-1 6-2 6-4.
There were several seeds to fall, however, with clay-court specialist Mariano Puerta beating 13th seed Ivan Ljubicic 7-5 7-5 6-2, and 22nd seed Nicolas Massu going down 6-7 (4-7) 6-2 6-2 6-4 to Stanislas Wawrinka.
After a series of disappointments at Roland Garros over the years, Safin was satisfied with his start.
"It's always special to play here and I was happy just to get past the first round," said Safin.
"It's tough in the first round, getting used to the balls and the courts and not having won many matches on clay this season, I had to work for every point against him."
Ferrero, the 2003 champion, is relegated to the role of dark horse as the 30th seed but is happy with his form.
"I just keep playing my game," he said. "I think I'm playing well. I've been playing well this season.
"If I'm not considered a favourite, well, that's all right. I think if I keep playing well, I might become a favourite."