Having opened the day with 6-2 6-4 second round win over Tathiana Garbin, Martinez, a two-time winner here, had little in reserve for Williams, who simply overpowered the 15th seeded Spaniard to stay on course for her fourth title of the season.
The holder of all four Grand Slam titles, Williams will now await the winner of an evening match between sixth seed Jelena Dokic of Yugoslavia and 13th seeded Russian Elena Dementieva.
In other third round action, third seed Lindsay Davenport downed 16th seed Clarisa Fernandez of Argentina 6-4 6-4.
In rain-delayed second round play, fifth seed Daniela Hantuchova of Slovakia advanced with a 6-2 4-6 6-3 win over Russia’s Tatiana Panova while former-French and Australian Open champion Mary Pierce disposed of seventh seed Anastasia Myskina 6-4 1-6 6-2.
Results:
Third round: Justine Henin-Hardenne bt Nathalie Dechy 2-6 6-3 6-2; Jelena Dokic bt Elena Dementieva 4-6 6-4 7-5; Mary Pierce bt Amanda Coetzer 6-3 1-6 6-0; Serena Williams bt Conchita Martinez 6-2 6-2; Daniela Hantuchova bt Jill Craybas 7-6 (12-10) 6-3; Lindsey Davenport bt Clarisa Fernandez 6-4 6-4; Ashley Harkleroad bt Meghann Shaughnessy 6-2 6-2; Vera Zvonareva bt Paola Suarez 6-4 6-4
Second round: Mary Pierce bt Anastasia Myskina 6-4 1-6 6-2; Daniela Hantuchova bt Tatiana Panova 6-2 4-6 6-3; Conchita Martinez bt Tathiana Garbin 6-2 6-4.
CASABLANCA: Defending champion and top seed Moroccan Younes El Aynaoui moved into the quarterfinals of the Grand Prix Hassan II tournament after ousting Swede Magnus Norman 6-4 3-6 6-3 on Thursday.
El Aynaoui will now meet Nicolas Massu for a place in the semi-finals after the Chilean beat Croatia’s Zelijko Krajan 2-6 6-1 6-4.
“The next match against Massu will not be easy. He is young, he hits hard and he’s confident,” El Aynaoui said.
The match of the day, however, was fought out between Argentine qualifier Frederico Browne and compatriot Franco Squillari.
The 27-year-old Browne saved a match point before overcoming Squillari 1-6 7-6 6-4 to reach the last eight, in a match lasting over two-and-a-half hours.
Squillari, ranked 90th in the world, thumped Browne in the first set, but the outsider’s spirits picked up in the second set, which he won 12-10 in the tiebreak. He then grabbed the third 6-4.
In Thursday’s other match fourth seed Dominik Hrbaty of Slovakia beat Hungary’s Attila Savolt 6-3 6-2.
ESTORIL, (Portugal): Results of quarterfinal matches from the $665,000 Estoril Open ATP/WTA tennis tournaments on Friday:
Men: 5-Tommy Robredo (Spain) beat Galo Blanco (Spain) 6-2 6-3; Nikolay Davydenko (Russia) beat 6-Yevgeni Kafelnikov (Russia) 6-2 6-4; 7-Max Mirnyi (Belarus) beat Feliciano Lopez (Spain) 7-6 (7-0) 6-4; Agustin Calleri (Argentina) beat 4-Fernando Gonzalez (Chile) 7-5 6-1
Women: Emmanuelle Gagliardi (Switzerland) beat Silvija Talaja (Croatia) 6-4 7-6 (7-4); 2-Magui Serna (Spain) beat Stephanie Cohen-Aloro (France) 6-3 6-2; 3-Virginie Razzano (France) beat Gisela Dulko (Argentina) 7-6 (7-4) 6-4; Julia Schruff (Germany) beat Ludmila Cervanova (Slovakia) 7-5 6-3—Reuters/AFP