Next up at Roland Garros for the German qualifier is Radwanska's elder sister and last year's Wimbledon finalist, Agnieszka.
Pfizenmaier, ranked 127 in the world, has already improved upon her best grand-slam result by upsetting the younger Radwanska and hopes there is a family resemblance when it comes to her sibling's game.
"Maybe she plays like her sister," she said after beating the 40th-ranked Urszula. "Yeah, let's try to do the same or do it better and have fun. That's the most important thing for me."