Third-seeded Jelena Jankovic of Serbia overcame tough resistance from Laura Robson of Britain on Wednesday before winning 6-4, 7-6 (8) to reach the second round of the e-Boks Open.
The 27-year-old Jankovic lost her serve five times but managed six breaks herself, and will face Russia's Yulia Putintseva in the second round. Fellow Serb Bojana Jovanovski also advanced by defeating Stefanie Voegele of Switzerland 6-3, 6-4.
Earlier Wednesday, fifth-seeded Kaia Kanepi of Estonia held on to beat Timea Babos of Hungary 7-5, 4-6, 7-6 (2) and reach the third round of the tournament.
In other second-round matches, Mona Barthel of Germany beat Alberta Brianti of Italy 6-3, 6-2, Croatia's Petra Martic ousted Johanna Konta of Australia 6-2, 6-3, and Alize Cornet of France overcame Patricia Mayr-Achleitner of Austria 6-2, 2-6, 7-5.