Top seed Nadia Petrova has departed the Bell Challenge at the quarter-final stage after retiring from her match against Melinda Czink in Quebec City.
The fifth seeded Czink had taken a first-set tie-break before her Russian opponent withdrew citing a viral illness.
The Hungarian now plays home hope Aleksandra Wozniak for a place in Sunday's final.
Wozniak, meanwhile, had an easy passage through to the semi-finals, defeating Russia's Alla Kudryavtseva 6-1 6-1.
Saturday's second semi will be contested by fourth seed Lucie Safarova of the Czech Republic and Germany's Julia Goerges.
Safarova beat American wild card Bethanie Mattek-Sands in straight sets while Goerges dispatched American qualifier Lilia Osterloh 6-2 6-4.
