Australian Jelena Dokic upset fourth seed Flavia Pennetta with a straight-sets victory in the second round of the Unicef Open on Wednesday.
Dokic, ranked 38 places below Pennetta at 59 in the world, took just one hour and four minutes to surprise the Italian with a 6-3 6-4 win in 's-Hertogenbosch, the Netherlands.
Awaiting Dokic in the quarter-finals is Swede Johanna Larsson.
Un-seeded Larsson battled past Belgian wildcard Kirsten Flipkens, winning 6-2 5-7 6-4 in two hours and 15 minutes.
Pennetta's exit proved to be the only surprise, as the other four seeds in action all won.
Belgian Yanina Wickmayer was one of those, but she did not have it all her own way - the third seed had to dig deep to overcome Spaniard Arantxa Parra Santonja 7-6 (7-4) 6-7 (6-7) 7-5 in two hours and 44 minutes.
Wickmayer will now face seventh seed Italian Roberta Vinci, who enjoyed a far easier time against Alexandra Dulgheru, beating the Romanian 6-2 6-1 in just 56 minutes.
Slovak Dominika Cibulkova, seeded fifth, also cruised in her match, dispatching German Kristina Barrois 6-0 6-1.
Cibulkova is unlikely to have such a straight-forward procession in the last eight, where she will face second seed Svetlana Kuznetsova.
Russian world number 12 Kuznetsova - a time-two Grand Slam winner - had to come from a set down to beat Italian Sara Errani 3-6 7-6 (7-3) 6-1.