Fourth seed Ekaterina Alexandrova needed three sets to edge past Stefanie Vogele in the round of 32 at the Luxembourg Open.
Russian Alexandrova was pushed to three sets by her Swiss opponent but ultimately outclassed Vogele to prevail 6-1 3-6 6-3 to book her place in the last 16.
She is joined there by compatriot Liudmila Samsonova, who overcame Misaki Doi 6-2 6-3, and eighth seed Alize Cornet, who beat Anastasia Potapova 6-4 6-2.
There were also wins for Clara Tauson, Jana Fett and Oceane Dodin.
At Zavarovalnica Sava Portoroz in Slovenia, meanwhile, there were victories for Viktoria Kuzmova, Sorana Cirstea and Lucia Bronzetti.