Sabine Lisicki booked a place in the quarter-finals of the Hawaii Open with a straight-sets win over Veronica Cepede Royg on Wednesday.
The German fifth seed came out on top from a tie-break in the first set, progressing 7-6 (7-2) 6-1 in the WTA 125k event.
She will face Jacqueline Cako in the last eight in Honolulu after the American overcame compatriot Jamie Loeb 3-6, 6-1, 7-5 in a tough battle that lasted over two hours.
Fourth seed Catherine Bellis advanced to the second round with a straight-sets win over Nannan Zhang, while sixth seed Evgeniya Rodina overcame Michaela Gordon 6-2 6-1.
Usue Maitane Arconada knocked out Miyu Kato of Japan, while Britain's Katie Swan scrapped past fellow wildcard Fanny Stollar 6-4 1-6 6-1.