ST. PETERSBURG, Russia (AP) — Australian Open champion Caroline Wozniacki's lost to Daria Kasatkina 7-6 (2), 6-3 in the quarterfinals of the St. Petersburg Ladies Trophy on Friday.

Kasatkina came back from a break down to win the first set in a tiebreaker before speeding to a 3-0 lead over the top-ranked Wozniacki in the second set.

The eighth-seeded Kasatkina, the last Russian left in the draw, will face France's Kristina Mladenovic in Saturday's semifinals. Mladenovic defeated Katerina Siniakova 6-4, 6-3.

Petra Kvitova of the Czech Republic continued her strong wild-card run with a 6-0, 6-2 win over French Open champion Jelena Ostapenko.

Kvitova's will face Julia Goerges of Germany, who defeated Russian qualifier Elena Rybakina 6-3, 6-3.