WTA roundup: Nao Hibino upsets defending champ Krejcikova in Livesport Prague Open

Ranked number 251 in the world, Hibino saved 15 of 22 break points and converted six of her 12 break chances against the home favorite. Krejcikova held 3-1 and 5-3 leads in the second set before letting the match slip away.

Hibino's quarter final opponent will be Czech 17-year-old Linda Noskova, who outlasted number five seed Alize Cornet (32) of France 7-5, 1-6, 7-6 (7). No. 1 seed Anett Kontaveit (26) of Estonia eliminated another Czech teen with a 6-4, 6-3 defeat of 17-year-old Lucie Havlickova. Kontaveit next faces number seven seed Anastasia Potapova (21) of Russia, a 6-4, 7-6 (8) winner over China's Lin Zhu (28).

Poland Open

Top-seeded Iga Swiatek (21) of Poland ran her clay-court winning streak to 18 matches with a 6-3, 6-2 defeat of Romania's Gabriela Lee (26) in second-round action in Warsaw.

Swiatek, who has not lost on the surface since the 2021 French Open quarter finals, fired 25 winners compared to just three for her opponent. She will face number five seed Caroline Garcia (28) in the quarter finals after the Frenchwoman's 6-3, 5-7 defeat of Italy's Elisabetta Cocciaretto (21).

Number eight seed Petra Martic (31) of Croatia had to work for a 6-3, 3-6, 6-3 win against Poland's Maja Chwalinska (20). Number 10 seed Jasmine Paolini (26) of Italy held off France's Clara Burel (21) 6-1, 6-7 (1), 6-0. Switzerland's Viktorija Golubic (29) rallied for a 6-7 (4), 6-2, 6-1 defeat of France's Kristina Mladenovic (29). Ukraine's Kateryna Baindl (28) advanced when Italy's Sara Errani (35) was forced to retire trailing 6-2, 3-0.