MADRID, Spain -- Third-seeded Conchita Martinez lost to Cara Black 6-2, 6-3 Tuesday in the first round of the Spanish Open.

In another upset, eighth-seeded Virginia Ruano lost to Klara Koukalova 6-2, 4-6, 6-1.

Sixth-seeded Magui Serna beat Austria's Patricia Wartusch 6-2, 6-2, while Conchita Martinez Granados beat countrywoman Marta Marrero 6-7 (5), 7-6 (3), 6-4 in a tough match that lasted nearly 3½ hours.

Top seeds Chanda Rubin and Alexandra Stevenson make their debut Wednesday.