World number one Iga Swiatek’s winning streak on clay came to an end as she suffered a quarter-final upset at her home tournament on Friday.
The 21-year-old Pole was 18-0 on clay this season, only dropping two sets while winning titles at Stuttgart and Rome, as well as the French Open.
But at the Poland Open she lost 6-1 1-6 6-4 to Caroline Garcia of France, who is ranked 45th in the world.
Garcia will now face Italy’s Jasmine Paolini in the semi-finals.
Paolini, ranked 58, recovered from a poor start to defeat Switzerland’s Viktorija Golubic 1-6 6-2 6-2.
Ukraine’s Kateryna Baindl will play Ana Bogdan of Romania in the other semi-final in Warsaw.