Italy's Flavia Pennetta beat Mariana Duque-Marino of Colombia 6-1, 4-6, 6-4 to advance to the second round of the clay-court tournament in Bastad on Sweden's west coast.
France's Virginie Razzano upset seventh-seeded Silvia Soler-Espinosa of Spain 7-5, 6-1. Spain's Arantxa Parra Santonija rallied past Alla Kudryavtseva of Russia 2-6, 6-4, 7-5, and Johanna Larsson also qualified for the second round after beating fellow Swede Sofia Arvidsson 6-1, 6-1.
Top-seeded Serena Williams will play her first game Tuesday, against Sesil Karatancheva of Kazakhstan.
Results from the first day of the WTA Swedish Open (x denotes seeding):
First round:
Arantxa Parra (ESP) bt Alla Kudryavtseva (RUS) 2-6, 6-4, 7-5
Johanna Larsson (SWE x8) bt Sofia Arvidsson (SWE) 6-1, 6-1
Virginie Razzano (FRA) bt Silvia Soler (ESP x7) 7-5, 6-1
Flavia Pennetta (ITA) bt Mariana Duque (COL) 6-1, 4-6, 6-4
Lourdes Domnguez (ESP x5) bt Anabel Medina Garrigues (ESP) 6-1, 6-2