Alicia Molik has set up a quarter-final clash with top seed Venus Williams after another thumping win at the Japan Open.
Molik, who upset sixth seed Akiko Morigami in the opening round, overpowered Canadian Aleksandra Wozniak 6-1 6-0.
Williams, meanwhile, beat countrywoman Vania King in straight sets 6-0 6-4 in the hard court event.
Three other seeded players in the women's draw also advanced to the quarters.
Eighth-seeded Italian Flavia Pennetta was taken to the limit in the second set against American qualifier Abigail Spears, but eventually captured the tie-breaker to complete the 6-4 7-6 (7-2) victory.
Pennetta will face her biggest test in her next match, when she takes on second-seeded Sania Mirza of India. The 20-year-old Mirza was the only seeded player who needed all three sets to advance to the last eight.
Mirza, the world No.29, outlasted Australian Casey Dellacqua to claim a 6-4 3-6 6-4 victory.
Coming off her first career title last week in Guangzhou, fifth seed Virginie Razzano of France advanced by downing qualifier Elena Baltacha of Great Britain 6-2 6-2.
Razzano will next face countrywoman Camille Pin, who upset third-seeded Russian Maria Kirilenko in the first round before coasting past Croatia's Jelena Kostanic Tosic 6-1 6-0.
Czech Klara Zakopalova beat Urszula Radwanska of Poland 6-2 3-6 6-2 to advance to the quarter-finals where she will face Denmark's Caroline Wozniacki, a 7-6 (7-3) 4-6 6-1 winner over qualifier Yuan Meng of China.
In the men's event, Lleyton Hewitt cruised into the third round after downing Slovakia's Luka Gregorc 6-3 6-3.
Hewitt, the No.4 seed, will face Spain's Ivan Navarro in the third round.
Top seed David Ferrer of Spain advanced to the third round with a 7-6 (7-5) 6-2 defeat of South African Wesley Moodie.
Ferrer will next face American Vincent Spadea, who upset 14th seed Sergio Roitman of Argentina in a three-set thriller.
After dropping the first set, Spadea came alive, winning the final two sets - including a third-set tie-breaker - to take the match 4-6 6-1 7-6 (9-7).
Fifth-seeded Jarkko Nieminen of Finland, No.11 Juan Martin Del Potro and No.15 Frank Dancevic were also sent packing.
Nieminen lost to Boris Pashanski of Serbia 6-3 4-6 6-4.
Pashanski will next face Dudi Sela of Israel, who rallied from a first set loss to steal the victory from Del Potro 2-6 7-5 6-3.
Dancevic was bounced from the tournament by German Rainer Schuttler, who claimed a 6-4 4-6 6-2 victory.
Schuttler will have his hands full in his next match when he faces third-seeded Richard Gasquet of France.
Gasquet, a 6-3 6-3 winner over American Zack Fleishman, is looking for back-to-back tournament victories after taking the title at last week's tournament in Mumbai.
Second-seeded Tomas Berdych of the Czech Republic had no trouble beating countryman Jiri Vanek 6-1 6-4 and will meet 16th seed Michael Russell in the next round.
Other seeds advancing to the third round were No.6 Dimitry Tursunov, No.7 Ivo Karlovic, No.8 Fernando Verdasco, No.9 Hyung-Taik Lee, No.10 Feliciano Lopez and 12th-seeded Thomas Johansson.
AIG Japan Open Tennis Championships, Tokyo
Men's Singles - Second Round
1-David Ferrer (Spain) bt Wesley Moodie (South Africa) 7-6 (7-5) 6-2
2-Tomas Berdych (Czech Republic) bt Jiri Vanek (Czech Republic) 6-1 6-4
3-Richard Gasquet (France) bt Zack Fleishman (USA) 6-3 6-3
4-Lleyton Hewitt (Australia) bt Luka Gregorc (Slovenia) 6-3 6-3
Boris Pashanski (Serbia) bt 5-Jarkko Nieminen (Finland) 6-3 4-6 6-4
6-Dmitry Tursunov (Russia) bt Paul Capdeville (Chile) 6-4 6-3