Second seed Kiki Bertens has secured her place in round two of the WTA Ladies Championship Gstaad.
The Dutchwoman, ranked 35th in the world, saw off Serbian Aleksandra Krunic 6-3 6-1.
Number four seed Mona Barthel, however, suffered an early exit when the German world number 50 lost 4-6 6-3 6-3 to Maria Sakkari of Greece.
There was, though, no such drama for her compatriot Carina Witthoeft, the sixth seed securing her place in the second round with a 6-3 7-6 (7/5) win over Spaniard Silvia Soler-Espinosa.
Slovakia's Rebecca Sramkova also progressed following a 6-3 6-4 victory against Serbian Nina Stojanovic, while American Louisa Chirico defeated Czech qualifier Tereza Smitkova 7-6 (7/5) 6-4.
German Anna Zaja set up a second-round clash against Bertens after she beat Patricia Maria Tig of Romania 6-2 6-3.
