Alicia Molik caused one of the upsets of the first round at the Japan Open after ousting sixth seed and local hope Akiko Morigami in straight sets.
The Australian, currently ranked 35th in the world after what has not been the greatest of seasons, proved far too strong in cruising to a 6-1 6-2 victory.
Morigami was not the only seeded player to suffer a first-round loss, with third-seeded Maria Kirilenko and fourth seed Ai Sugiyama joining her on the sidelines.
Kirilenko, the 26th ranked player in the world from Russia, went down 6-3 4-6 6-3 to Frenchwoman Camille Pin. Pin will next face unseeded Croatian Jelena Kostanic Tosic, who defeated Spain's Lourdes Dominguez Lino 6-4 6-4.
Local favourite Sugiyama, ranked 37th in the world, was dominated by qualifier Meng Yuan of China. Yuan disposed of Japan's Sugiyama in straight sets 6-3 6-3.
Yuan will face Caroline Wozniacki of Denmark in the second round while Molik takes on Canadian Aleksandra Wozniak.
Top-seeded American Venus Williams found little trouble in advancing to the second round, taking care of countrywoman Jill Craybas 6-3 6-1.
Williams will face another American, Vania King, in the second round. King needed all three sets to advance, eventually overcoming Romanian Edina Gallovits 6-2 5-7 7-5.
Eighth-seeded Flavia Pennetta of Italy was pushed to the limit in the first set by American Ahsha Rolle before cruising to victory in the second set to pick up a 7-5 6-1 triumph.
Other winners on the women's side in the first round included fifth-seeded Virginie Razzano of France and No.8 Flavia Pennetta of Italy.
Defending champion Marion Bartoli of France is not entered in the draw.
With all 16 seeds receiving a first-round bye in the men's draw, Hyung-Taik Lee of Korea and American Sam Querrey were the first seeded players to step on the hard courts.
Querrey, the 13th seed, continued the trend of fallen seeds, losing to Spain's Ivan Navarro 7-5 6-3 on Tuesday in their second-round match.
While Querrey did not make it out of the second round, the ninth-seeded Lee advanced with ease, routing unseeded Yen-Hsun Lu of Taipei 6-1 6-4.
The top seed in the men's draw is David Ferrer, a two-time winner on the tour this season. A semi-finalist at the US Open, the Spaniard absorbed a first-round loss in his only previous showing here in 2002.
Ferrer will open up against South Africa's Wesley Moodie, a 7-6 (8-6) 7-6 (10-8) winner over Simone Bolelli of Italy.
Other first-round winners were Americans Justin Gimelstob and Vincent Spadea, Czech Jiri Vanek and Marin Cilic of Slovakia.
AIG Japan Open, Tokyo
Men's Singles – 1st Round
Vincent Spadea (USA) bt Amer Delic (USA) 6-3 6-1
Robert Kendrick (USA) bt Hyun- Woo Nam (Korea) 7-6 (7-5) 6-7 (7-9) 6-3
Luka Gregorc (Slovakia) bt Takahiro Terachi (Japan) 6-4 6-4
Benjamin Becker (Germany) bt Takao Suzuki (Japan) 7-5 3-6 6-4
Boris Pashanski (Serbia) bt Jean-Claude Scherrer (Switzerland) 7-6 (7-5) 1-6 7-5
Dudi Sela (Israel) bt Simon Stadler (Germany) 6-4 7-5
Rainer Schuettler (Germany) bt Go Soeda (Japan) 6-3 1-6 6-2
Justin Gimelstob (USA) bt Lukasz Kubot (Poland) 6-4 7-5
Marin Cilic (Croatia) bt Woong-Sun Jun (Korea) 6-2 6-2
Jiri Vanek (Czech Republic) bt Satoshi Iwabuchi (Japan) 6-4 6-4
Men's Singles – 2nd Round
9-Hyung Taik Lee (Korea) bt Yen-Hsun Lu (Taipei) 6-1 6-4
Ivan Navarro Pastor (Spain) bt 13-Samuel Querrey (USA) 7-5 6-3
Women's Singles – 1st Round
1-Venus Williams