Mirra Andreeva crashed out of the Berlin Open after suffering a shock first-round defeat to Magdalena Frech.
The 18-year-old lost 2-6Â 7-5Â 6-0 to her Polish counterpart, who will face either Amanda Anisimova or Bianca Andreescu in the next round.
Despite losing her serve first, Andreeva broke Frech three times in the first set and looked on course for a straightforward win on the grass.
Frech fought back hard in the second, taking a 4-1 lead before eventually taking the set 7-5 to level the match.
Andreeva was then completely blown away in the final set as Frech completed her victory in style with her second match point.
The match was over in two hours and 11 minutes as Frech joined world number one Aryna Sabalenka, French Open champion Coco Gauff, and Jessica Pegula in the last 16.
Data Debrief: Learning curve for Andreeva
After reaching the quarter-finals of the French Open, Andreeva would have been hoping for a good start to her grass-court season.
Instead, she lost a deciding set with a 6-0 scoreline for the first time in her professional career (all levels and qualifying draws included).
Frech, meanwhile, claimed just her second win over an opponent ranked inside the WTA's top 10.
