Eugenie Bouchard came through her Coupe Banque Nationale opener with a minimum of fuss as two seeds departed.
Bouchard, the top seed at the WTA International event in Quebec City, brushed past Mandy Minella 6-3 6-4 on Wednesday.
The Canadian, who suffered a first-round loss at the US Open, broke serve four times to win in one hour, 24 minutes.
It was an otherwise bad day for the seeds as Evgeniya Rodina and Samantha Crawford fell in straight sets in second-round matches.
Crawford coughed up 10 double faults in a 6-4 6-1 loss to fellow American Lauren Davis.
Seventh seed Rodina, meanwhile, slumped to a 6-4 6-3 defeat against Julia Boserup.
Teenager CiCi Bellis continued her run, reaching the quarter-finals with a 6-4 4-6 6-3 win over Danielle Lao.
Qualifier Tereza Martincova is also into the last eight after overcoming Ekaterina Alexandrova 6-4 1-6 6-4.