Friday 2 February 2018 18:48, UK
Australian Open champion Caroline Wozniacki suffered a quarter-final defeat to Russia's Daria Kasatkina at the St Petersburg Ladies' Trophy on Friday.
The Dane was edged out 7-6 6-3 by Russia's world no 23 Kasatkina in her first tournament since lifting her maiden Grand Slam title in Melbourne less than a week ago.
Wozniacki returned to the world no 1 spot with victory over SImona Halep in a breathtaking women's final and her exertions in the year's opening major took their toll after a second-round victory earlier in the week.
20-year-old Kasatkina was dominant in the tiebreak to claim the opening set and won three of the last four games of the match against Wozniacki, who had fought hard to get back on serve halfway into the second set.
"She just won the Australian Open, and since I beat her, it means I was playing really well," said Kasatkina said.
"I was just trying to play point-by-point and focus on the rally."
Kasatkina will next face defending champion Kristina Mladenovic, who continued her strong run with a 6-4 6-3 win over Czech Katerina Siniakova in the quarter-finals.
Earlier in the day, two-time Wimbledon winner Petra Kvitova booked her place in the semi-finals with an attacking masterclass to defeat second seed Jelena Ostapenko 6-0 6-2.
Kvitova, who entered the tournament as a wildcard, broke her Latvian opponent's serve five times to seal the most one-sided victory in the pair's five head-to-head meetings.
"At the end of the last match, I found my rhythm a little bit - I knew I had to play a little bit better today, against someone who is playing very aggressive," said Kvitova, who will next face Julia Goerges.
"I had to stay focused on every point. It was just about a few games which I was serving and kept my serve... I served pretty well today, so it was great."
