Making her debut at the Amelia Island tournament, Hingis beat Virginia Ruano-Pascual of Spain and 15th seed Henrieta Nagyova of the Czech Republic in her first two matches after receiving a first-round bye.

Sanchez-Vicario, a two-time champion who last reached this semifinal in 1996, ousted ninth seed Paola Suarez of Argentina in a third-round match.

Hingis has won their four meetings on clay since 1997 -- all in straight sets. She has captured all WTA Tour Tier I tournaments and three of the four Grand Slam events but has not won this event, which has been claimed by all the other No. 1 players in the last 20 years.

Third seed Elena Dementieva of Russia is matched against No. 6 Amelie Mauresmo of France in the quarterfinals.

Dementieva has won 12 of her last 15 matches, including a 6-4, 6-3 victory over 16th seed Elena Likhovtseva in the third round.

The 2000 Olympic silver medalist reached her first WTA Tour final at the Mexican Open last month.

Mauresmo extended her winning streak to 12 matches with a thrilling 7-6 (7-3), 4-6, 6-3 victory over 12th seed Lisa Raymond. Mauresmo won titles in her homeland at Paris and Nice in February.

Fourth seed Amanda Coetzer of South Africa will be bidding for her third semifinal berth at Amelia Island when she faces No. 10 Meghann Shaughnessy of the United States.

Coetzer only surrendered four games in her straight-sets victory over Shaughnessy in their claycourt encounter at the last year's Antwerp event.

Coetzer prevailed in a tough third-round match against No. 13 Jelena Dokic of Yugoslavia, 6-4, 2-6, 6-3

Shaughnessy, who is celebrating her 22nd birthday, beat fellow American Meilen Tu, 4-6, 7-5, 6-0, in the third round.

The night quarterfinal match features unseeded players Silvia Farina Elia of Italy and Nadia Petrova of Russia.

Farina Elia knocked off second seed Conchita Martinez of Spain in the second round and followed with a 6-4, 6-2 win over Maria Emilia Salerni of Argentina.

Petrova downed American Jill Craybas, 6-1, 7-6 (8-6) in the third round.