Petra Kvitova, the former Wimbledon champion from the Czech Republic, continued her exciting return to form here on Wednesday with a performance which edged her nearer the tenth title of her career.
Kvitova's brilliantly masked hitting eased her into the quarter-finals of the $2,000,000 Dubai Open with a 7-5, 7-6 (7/1) win over Ana Ivanovic, the former French Open champion from Serbia.
It sets her up with a last eight match against Agnieszka Radwanska, the defending champion, and who she has painful memories of as the Pole beat her in the end of year Istanbul tournament last year.
Kvitova's match was full of fine ground strokes between two players who are gradually regaining some of their former excellence after fitness problems.
It lurched unpredictably, first one way and then the other.
Kvitova led 5-1 in the first set and 5-3 in the second and both times Ivanovic increased her ratio of early attacks and worked her way back to parity.
However Kvitova's outstanding facility for disguise tipped the balance.
"From the forehand I can think about going for every point a hundred percent and make winners from that side," she said.
Radwanska had to work hard to get past Yulia Putintseva, an 18-year-old wild card player from Kazakhstan, by 7-5 6-3.
Radwanska acknowledged the promise of her opponent.
"I really want to see her, you know, in a couple of months, how she's gonna play and what her ranking is going to be," the world number four from Poland said.
Kvitova was not displeased with this quarter-final draw.
"I played her last time Istanbul and I lost to her," she said with a blunt look, which recalled that in the process she also lost her WTA Championship season-end title.
"I'm looking for revenge, for sure."
Both players title hopes were boosted after the withdrawal of world number one Serena Williams earlier on Wednesday with a back injury. This followed Monday's withdrawal of top-seeded Victoria Azarenka with a heel injury.
Another reason for Kvitova's fine form, which saw her lead Williams 4-1 in the final set in Doha last week, is the improvement in her physical fitness compared with last year.
"I changed my fitness coach," she says.
"So it's different exercises, and working on different muscles. I have to get used to that and continue with it and to show it on the court then."
Another who might capitalise on the absence of the top two is Caroline Wozniacki, the former world number one from Denmark who won the title here two years ago.
She also looked in good form as she overwhelmed Zheng Jie, the former Wimbledon semi-finalist from China, by 6-0, 6-1.
Wozniacki looks fitter too and is trying to reproduce the movement and consistency which got her to the top in 2010 and 2011.
She was asked to explain the curiosity of her father-coach Piotr coming on to court to offer advice despite her rampant first set performance.
"It's just because we practise a lot of things," said Wozniacki. "He gives me some pointers, about what I need to remember, what we have practiced, and what can still be improved.
"It doesn't matter if you win 6-0 or 6-3, at the end of the day you want to win but you also want to try a few of the things that you have been practising."
Wozniacki next plays Marion Bartoli, the former Wimbledon finalist from France, who enjoyed her second piece of rare luck in this tournament by receiving a walk-over from Williams.
Bartoli was earlier given a wild card into the tournament after submitting her entry late.