GSTAAD, Switzerland -- Second-seeded Juan Carlos Ferrero was upset by fellow Spaniard David Sanchez 5-7, 6-4, 6-3 Thursday in the second round of the Swiss Open, leaving just two seeded players in the tournament.

Sanchez, ousted in the opening round at Wimbledon, will join the two bottom-seeded players in the quarterfinals: No. 7 Gaston Gaudio of Argentina and two-time champion Alex Corretja of Spain, No. 8.

Corretja, returning to action for the first time since his semifinal exit at the French Open last month, is seeking to become the first player since Sergi Bruguera to win three titles in Gstaad. Corretja, the champion in 1998 and 2000, will face Sanchez in the quarterfinals.

Gaudio reached the round of eight by defeating Russian Mikhail Youzhny 7-6 (3), 6-4. Corretja advanced with a 6-4, 6-4 victory over 1997 champion Felix Mantilla.

Home favorite Marc Rosset upset fourth-seeded Andrei Pavel of Romania 7-5, 7-6 (1). Rosset will oppose Claudio in the quarterfinals.