Sabine Lisicki and Eugenie Bouchard booked their places in the quarter-finals of the Malaysia Open with straight-set victories on Wednesday.
Third seed and world number 31 Lisicki struggled in the opening set of her match against Barbora Krejcikova - ranked 160 places below her - and was forced to save four break points before eventually taking the advantage.
Krejcikova was unable to provide a similar level of resistance in the second set, producing four double faults, and Lisicki was relatively comfortable in earning a 7-5 6-3 win.
The German is joined in the last eight by sixth seed Eugenie Bouchard, who took just over an hour to defeat Kurumi Nara 6-1 6-2.
Bouchard won 13 of a possible 15 points from her first serve to race into a one-set lead, and she did not let up in the second, breaking twice to seal an easy victory.
Seventh seed Su-wei Hsieh suffered a premature exit at the hands of Kristina Kucova, the Slovakian winning 6-1 3-6 6-3.
Kucova will face the winner of Risa Ozaki and Elina Svitolina - the highest seed remaining in the competition - in the next round.
Qiang Wang overcame fellow Chinese Ying-Ying Duan to advance, winning 6-4 6-4.