Kiki Bertens started her bid for a third consecutive Nuremberg Cup title with a straight-sets win over Dejana Radanovic on a day which saw three of the top five seeds bow out.
The third seed from the Netherlands has now won 13 consecutive matches in the main draw in Nuremberg after schooling Radanovic 6-1 6-1.
Bertens needed only 61 minutes to end Radanovic's first match on the WTA main draw as she attempts to complete a hat-trick, breaking the 293rd-ranked Serbian six times.
A trio of players that Bertens might have considered to pose a big threat made early exits, with Julia Goerges, Zhang Shuai and Irina-Camelia Begu going out.
Second seed Goerges lost 6-2 6-7 (8-10) 7-6 (7-5) to Kristyna Pliskova, while fourth seed Zhang was thrashed 6-2 6-2 by Fanny Stollar and Begu - seeded five - retired at 6-4 3-3 down to Johanna Larsson.
Alison Riske, Nadia Podoroska, Katerina Siniakova made it through, while Mona Barthel and Alison Van Uytvanck were leading when play was suspended due to rain.
Third seed Anastasia Pavlyuchenkova inflicted a humiliating double bagel on Tatjana Maria in the opening round of the Internationaux de Strasbourg.
Defending champion Sam Stosur eased to a 6-3 6-2 win over over Sofia Kenin and top seed Ashleigh Barty advanced with a 6-4 6-4 success over Luksika Kumkhum.
Last year's runner-up Daria Gavrilova was another Australian to make it through at the expense of Jennifer Brady, with Dominika Cibulkova, Timea Babos and Hsieh Su-Wei the other seeds who were winners on day two.