Eugenie Bouchard's poor year continued with a second-round loss at the Coupe Banque Nationale on Thursday.
The Canadian top seed has endured a tough 2016, and it continued with a 6-2 6-3 loss to Russian Alla Kudryavtseva.
Bouchard had won the only previous meeting between the pair comfortably, but was beaten in just over an hour in Quebec City.
The 2014 Wimbledon runner-up has battled this year, failing to go beyond the third round of any of the grand slams.
Kudryavtseva broke serve five times to reach the quarter-finals, where Lauren Davis awaits.
Alison Van Uytvanck continued her run to the last eight, beating lucky loser Barbora Stefkova 6-4 6-3.
Oceane Dodin overcame Sachia Vickery 6-4 6-4 and Jessica Pegula edged past teenage wildcard Francoise Abanda 7-6 (7-2) 7-5.