million French Open tuneup.
Hewitt, a semifinalist here a year ago, beat 18-year-old Philipp Kohlschreiber of Germany, 7-5, 6-4. The 21-year-old Australian has won two titles this season but is just 4-3 on clay.
One player Hewitt will not meet in later rounds is American Andre Agassi, the ninth seed, who withdrew Monday.
Agassi's departure came one day after he captured his first claycourt title in three years with a 6-3, 6-3, 6-0 rout of No. 7 Tommy Haas of Germany on Sunday at the $2.33 million Tennis Masters Series -- Rome.
Max Mirnyi of Belarus registered an upset Monday, defeating No. 12 Pete Sampras of the United States, 6-3, 6-4.
In other matches Monday, third seed Juan Carlos Ferrero of Spain was upset by countryman Albert Costa. A former champion, Costa posted a 2-6, 6-3, 6-4 victory. Ferrero has lost three of his last five matches since capturing the Tennis Masters Series
event in Monte Carlo. He reached the final here last year but lost to Albert Portas in five sets.
Costa, who won this tournament in 1998, lost to Ferrero in the semifinals last season.
Portas will not defend his crown as he was defeated by Bjorn Phau of Germany, 6-4, 6-2.
Fourth seed Yevgeny Kafelnikov of Russia also was ousted, suffering his first career loss to Spain's Alex Corretja. Kafelnikov had won 10 straight sets against Corretja before the Spaniard recorded a 6-1, 6-2 rout Monday. Kafelnikov dropped to 3-6 on clay this season.
Max Mirnyi of Belarus also registered an upset Monday, defeating No. 12 Pete Sampras of the United States, 6-3, 6-4.
Fifth seed Tim Henman of Britain, No. 15 Guillermo Canas of Argentina and 16th-seeded Younes El Aynaoui of Morroco all were victorious Monday. Henman cruised to a 6-4, 6-2 triumph over Nicolas Escude of France, Canas defeated Belgium's Xavier Malisse, 7-5, 1-6, 6-0, and El Aynaoui got past Frenchman Fabrice Santoro.
Six other matches involved unseeded players: Stefan Koubek of Austria posted a 7-5, 6-1 win over qualifier Anthony Dupuis, Carlos Moya of Spain overcame qualifier Mikhail Youzhny, 6-3, 2-6, 6-4, Sjeng Schalken of the Netherlands eliminated Switzerland's Michel Kratochvil, 6-4, 6-4, Spain's Alberto Martin beat David Nalbandian of Argentina, 6-4, 6-3, qualifier Julien Boutter defeated Spain's Albert Montanes, 7-6 (7-2), 6-4, and Wayne Ferreira of South Africa got by qualifier Olivier Rochus, 4-6, 7-6 (7-0), 6-4.