Danielle Collins of the U.S. and Donna Vekic of Croatia knocked off the second and third seeds Friday night in the quarterfinals of the San Diego Open and will face one another in one semifinal on Saturday.

Collins twice broke Paula Badosa’s serve in their first set tiebreaker en route to beating the second-seeded Spaniard 7-6 (5), 6-4.

Earlier Friday, Vekic dominated third-seeded Aryna Sabalenka of Belarus in the third set to win their quarterfinal match 6-4, 6-7 (5), 6-1.

Vekic missed a chance to wrap up her match in the second set tiebreaker when she lost her serve on consecutive points and fell behind 6-5, before Sabalenka won on set point. However, Vekic took over after that, breaking Sabalenka twice in the third set.

In the tournament’s other quarterfinals, the top seed and world No. 1 player Iga Swiatek of Poland needed just over an hour to finish off Coco Gauff of the U.S. 6-0, 6-3.

Swiatek’s next match will be against fourth-seeded Jessica Pegula of the U.S., who defeated countrywoman Madison Keys 6-4, 7-5.

Transylvania Open

Second-seeded Anhelina Kalinina of Ukraine won her first set against Anna Blinkova of Russia but fell apart thereafter, losing to the 138th-ranked Blinkova 6-7 (7), 6-1, 6-3 in the quarterfinals at Cluj-Napoca, Romania.

Blinkova unloaded five aces to Kalinina’s one, and the Russian also dominated in first-serve points won, 70 percent to 59 percent, and break points saved, 75 percent to 54 percent.

Kalinina took the first set tiebreaker on her third set point, but then had her serve broken three times in the second set and once more in the third.

Blinkova advances to face fourth-seeded Anastasia Potapova of Russia, who defeated the eighth-seeded Anna Bodnar of Hungary 7-7, 3-6, 6-1.

In the other semifinal, Xiyu Wang of China, the seventh seed, will meet Jasmine Paolini of Italy.

Wang defeated Nuria Parrizas Diaz of Spain 6-1, 7-6 (5), and Paolini also won in straight sets, 7-5, 7-5 over Jule Niemeier of Germany.

–Field Level Media