Agnieszka Radwanska cruised into the quarter-finals of her home event, the Katowice Open, with a 6-3 6-1 success against An-Sophie Mestach.
The world number nine needed just an hour and 13 minutes to seal her place in the last eight and a meeting with Klara Koukalova.
Radwanska required only one break of serve to take the first set. And the 103-place gap in the rankings became evident in the second as the Pole raced to an easy triumph.
Kirsten Flipkens battled her way into the quarter-finals with a come-from-behind 6-7 (6-8) 6-1 6-4 victory over Monica Niculescu.
Belgian Flipkens lost a tight first set, in which there four breaks of serve, in a keenly contested tie break, but the seventh seed rebounded to win through in a match that lasted two and a half hours.
However, fifth seed Kaia Kanepi was dumped out as lucky loser Elizaveta Kulichkova continued to make the most of her reprieve this week with a dominant 6-1 6-2 victory.
Estonian Kanepi is ranked some 73 places above Kulichkova, but the world number 123 broke serve on six occasions to book her spot in the last eight in under an hour.
There was better news for eighth seed Anna Karolina Schmiedlova, as the eighth seed had to overcome a second-set blip to progress 6-1 3-6 6-3 against Katerina Siniakova.