The 35-year-old Maria won her round of 16 versus the Hungarian Anna Bondar with 6: 3, 6: 2.
In the quarter-finals, Maria fulfills 8 Czech Tereza Martincova or the French woman Diane Parry.
After a 4-0 lead in the initial collection, Maria needed to be treated for around 15 minutes, yet she was able to continue playing later on.
Early breaks in both sentences led her way to success.
In Granby, the 92nd is the only German starter of the world positions, Maria is among 4 German females in the main area at the US Open (from August 29).
Samsonova as well solid for triumph
Laura Siegemund (Metzingen) left at the WTA event in Cleveland/Ohio in the round of 16.
The 34-year-old lost to Russian Ludmilla Samsonova 2: 6, 1: 6.
Siegemund thus missed her initial quarter-finals on the WTA scenic tour in Stuttgart because April.
The globe rankings-216 was in Cleveland.
The only German at the beginning.