Sergio Roitman upset third-seeded Juan Ignacio Chela in straight sets on Tuesday in the first round of the Orange Prokom Open, while Austria's Stefan Koubek rallied to beat fifth-seeded Agustin Calleri.
Roitman beat Chela 6-1, 6-2 in the all-Argentine match on clay at Sopot Tennis Club, while Koubek recovered from a disastrous first set to beat Calleri 0-6, 7-6 (3), 7-5.
Chela and Calleri joined No. 4 Filippo Volandri and No. 6 Nicolas Almagro, who were eliminated in first-round matches on Monday. No. 8 Potito Starace of Italy also went out on Tuesday, retiring in the third set against Boris Pashanski of Serbia, who led 6-7 (4), 6-2, 3-1.
Second-seeded Tommy Robredo nearly added to the first-round victims list. Poland's Lukasz Kubot rallied from a 4-1 deficit to tie the third set against Robredo 5-5, before the Spaniard won 6-4, 5-7, 7-5.
Two seeds did advance on Tuesday, led by No. 1 Nikolay Davydenko of Russia, who beat Romania's Andrei Pavel 6-3, 6-4.
He moved on along with No. 7 Florian Mayer of Germany, who defeated Juan Pablo Brzezicki of Argentina 6-3, 6-3.
In other matches, Igor Andreev of Russia completed a 6-0, 6-4 victory over Nicolas Lapentti of Ecuador in a match that was suspended on Monday because of rain.
Olivier Patience of France beat Dawid Olejniczak of Poland 7-6 (0), 6-4, Martin Vassallo Arguello beat Maximo Gonzales 2-6, 6-3, 6-2 in another all-Argentine match and Belgium's Kristof Vliegen defeated Luis Horna of Peru 6-2, 6-7 (8), 6-3.
Top-seeded Anabel Garrigues beat Germany's Sandra Kloesel 6-3, 7-6 (5) on Tuesday in the first round of the Nordic Light Open.
Tournament wild-card Emma Laine rallied to beat Czech Eva Birnerova 6-2, 6-7 (4), 6-1, and will next play eighth-seeded Vera Dushevina from Russia.
Laine, a 21-year-old Finn, was making her comeback after taking three months off with a virus.
Youlia Fedessova of France ousted fourth-seeded Kaia Kanepi from Estonia after a difficult first-set tiebreaker.
Danish teen Caroline Wozniacki defeated Lithuania's Lina Stanciute 7-6 (4), 7-5; and Virginia Pascual of Spain defeated Chan Chin-wei of Taiwan 6-4, 3-6, 6-2.