Dominika Cibulkova of Slovakia and Italy's Roberta Vinci were among the winners Sunday in the first round of the Pan Pacific Open.
Play was limited to the enclosed center court because of rain and only five matches were completed.
The 12th-seeded Cibulkova earned a 6-3, 7-6 (7-3) victory over Spain's Anabel Medina Garrigues, while the 14th-seeded Vinci went the distance in a 6-4, 4-6, 7-5 triumph over Czech Barbora Zahlavova Strycova.
Other winners were Serbia's Jelena Jankovic, Japanese wild card Ayumi Morita and Croatia's Petra Martic.
Jankovic eased past Belgian Yanina Wickmayer, 6-3, 6-3, while Morita posted a 6-2, 3-6, 6-2 win over Romania's Sorana Cirstea and Martic rallied for a 0-6, 6-4, 6-3 victory over Germany's Andrea Petkovic.
First-round play continues Monday, weather permitting, with 19 matches.
The top eight seeds, including Victoria Azarenka, Maria Sharapova, Agnieszka Radwanska and Petra Kvitova, all received byes into the second round.