Eugenie Bouchard won 12 of the last 13 games on Wednesday for a straight sets victory at the Strasbourg International.
The 19-year-old from Westmount, Que., defeated Camila Giorgi of Italy 6-3, 6-0 to reach the quarter-finals at the clay court event, which serves as a tune-up for next week's French Open.
Giorgi is ranked 88th in the WTA rankings, five spots ahead of Bouchard.
But Giorgi self-destructed with seven double faults, while Bouchard won 70 per cent of the points on her first serve.
Bouchard next faces Anna Tatishvili. The Georgia downed the fifth seed Monica Niculescu of Romania, 4-6, 6-3, 6-2.
The fourth-seeded Hsieh Su-wei of Taiwan Hsieh lost 6-4, 4-6, 7-6 (3) to Misaki Doi of Japan, while seventh-seeded Chanelle Scheepers of South Africa reached the quarters by beating American Shelby Rogers 2-6, 6-3, 6-4.
Flavia Pennetta, Johanna Larsson and Lucie Hradecka also advanced to the last eight.
Later Wednesday, third-seeded Alize Cornet was scheduled to play Magda Linette.