Mona Barthel was a surprise casualty in the first round of the Coupe Banque Nationale after being dumped out by Jelena Ostapenko in three sets on Monday.
Barthel, seeded third, was one of the favourites in Quebec but went down 7-6 (8-6) 4-6 6-4 to an opponent ranked 53 places below her in the WTA world rankings.
The German had a set point in the opener and was a break up early in the decider, but was unable to find a way past Ostapenko on the indoor carpet courts.
Barthel was the only seed in action on Monday, but in other matches Andrea Hlavackova defeated Shelby Rogers 7-6 (10-8) 6-0, while Sesil Karatantcheva saw off Barbora Krejcikova 6-3 7-5.
Also on Monday, Great Britain’s lucky loser Naomi Broady was a 6-3 7-6 (9-7) victor over Alla Kudryavtseva and Louisa Chirico defeated American compatriot Julia Boserup 7-5 4-6 6-1.