Wimbledon champion Petra Kvitova and Victoria Azarenka roared into the semi-finals of the WTA Championships with impressive victories as world number one Caroline Wozniacki's tournament looked in danger of a premature end on Thursday.
Czech Kvitova cruised past a weary Wozniacki 6-4 6-2 to qualify from the Red Group with a match to spare after Azarenka trounced China's Li Na 6-2 6-2 to guarantee a top-two place in the White Group.
Wozniacki, who will end the year on top of the rankings for a second consecutive season, needed to have her blood pressure checked at the end of the first set as the effects of two long three-setters in two days seemed to catch up with her.
The Dane, who posted just one win in her round-robin matches, looked ready for a holiday by the end although should Poland's Agnieszka Radwanska beat Vera Zvonareva later, but drop a set in the process, Wozniacki would have to delay her flight home until at least after the final round-robin matches on Friday.
World number four Azarenka, who arrived in the Turkish city on the back of winning the title in Luxembourg last week, has been the most impressive of the eight players on display so far, although Kvitova is not far behind.
The 22-year-old has dropped just eight games in beating U.S Open champion Samantha Stosur and French Open champion Li and looks in the mood to finish the year on a high and collect a possible $1.75 million jackpot.
"I'm really enjoying playing, I think I improved a lot," Azarenka told reporters. "It was a good preparation for me what I did in Luxembourg, to get that momentum."
After Li fired a forehand long to end the one hour 32 minute contest, Azarenka looked ecstatic and is clearly inspired by the atmosphere generated by around 11,000 fans inside the cavernous Sinam Erdem Arena.
"I'm always pumped up. I play a bit hard, and I was glad I could finish strong," she said.
"The crowd is amazing. I think that's what we've been really missing in the last couple years, the good crowd, the good support," added Azarenka who failed to survive the group stages the last two years when the event was held in Doha.
For Li, who beat Maria Sharapova in her opening match, the equation is now quite straightforward.
The winner of her match against Stosur on Friday will join Azarenka in the semi-finals from the White Group.
"It's just like a normal tournament now," the 29-year-old said. "The winner can go in the draw, and the loser have to go back. Yeah, it's tough.
"So I think both of us will be fighting a lot."