Top seeded duo Dominika Cibulkova and Yanina Wickmayer have both crashed out of the Bell Challenge in Quebec.
No.1 seed Cibulkova won the first set against Kirsten Flipkens in their opening round clash but the Slovakian was stunned as her Belgian opponent hit back to secure a 2-6 6-3 7-5 victory.
Cibulkova, the world No.13, led 5-4 in the decider but Flipkens refused to buckle and claimed the next three games for a shock success.
Wickmayer was swept aside in her second round clash with the No.2 seed falling to a 6-1 6-1 drubbing against American teenager Lauren Davis inside 63 minutes.
Third seed Mona Barthel fared much better and booked her quarter-final spot with a routine 6-2 6-1 win over Petra Rampre.
Kristina Mladenovic defeated Annika Beck 4-6 6-4 6-3 while sixth seed Barbora Zahlavova Strycova eased past Tatjana Malek 6-3 6-3.