Caroline Wozniacki's eighth attempt at reaching the Sydney International semifinals wilted in the stifling Australian heat on Wednesday with the former world number one going down to Barbora Strycova in a three-set slugfest.

Strycova prevailed 7-5, 6-7(6), 6-4 over her 10th seeded Danish opponent in a three-hour and 20 minute marathon played out in temperatures of around 40 degrees Celsius at the Ken Rosewall Arena. 

The 30-year-old Czech next meets second seed Agnieszka Radwanska, who beat Chinese qualifier Duan Yingying 6-3, 6-2 in the last quarterfinal of the day at the Australian Open warmup event.

Wozniacki has never progressed beyond the quarterfinals in Sydney and she appeared to be heading for a straight-sets defeat when Strycova claimed the opener and raced to a 5-0 lead in the tiebreaker of the next.

Wozniacki, however, won seven of the next eight points to force a decider but the unseeded Strycova reeled off the last three games to seal victory under the scorching sun.

"You just try and think like you're on a beach drinking pina coladas," Wozniacki joked.

"That's basically your train of thought. You know that it's the same for both players, so I was just trying to mentally just try and keep cool. But it was really, really hot out there.

"On the positive side of things, I can eat whatever I want now because I have burned a lot of calories today," she said.

Canadian Eugenie Bouchard and British number one Johanna Konta kept it simple in their quarter-finals to set up a last four showdown after straight-set victories.

Sydney-born Konta, the sixth seed, won 6-3 7-5 against Russian teenager Daria Kasatkina, who had stunned world number one Angelique Kerber in the second round.

Former Wimbledon finalist Bouchard beat Russian Anastasia Pavlyuchenkova 6-2, 6-3 to continue her good early season form after a dismal couple of years following her breakthrough campaign in 2014.

"I don't want to get too happy after a win or too sad after a loss, so, for me, it's just a good step in the right direction," the Canadian world number 49 said.

"I know there is a long way to go to achieve what I want.

"To match up against solid players like I have this week, it's a very tough tournament here. So I'm proud of that, for sure."

Source :Times Of Oman