American Sloane Stephens crashed out of the Qatar Total Open Wednesday in the biggest upset of a windy and warm Day Three at the WTA Premier event in Doha.

The rising star and Australian Open semi-finalist squandered a one set lead and four match points against Klara Zakopalova before falling to the Czech in a three-set, two hour and forty minute thriller 4-6, 7-6(5) 7-6(5).

It was an object lesson in killer instinct for the 19-year old American that the world number 17 will need to full absorb if she's to mount a serious challenge on the top ten later this year.

"Today was a tough match," said Stephens. "The conditions were tough but Klara played well. Now I just need to regroup and keep working on my game and get ready for Dubai."

The win for Zakopalova sets up an interesting tie Thursday on Centre Court against world number three Maria Sharapova.

The two have met three times in the past, with the four-time Grand Slam winner taking each match, including a hugely entertaining three-setter on the clay last year in the fourth round of the French Open.

Elsewhere in Doha the top seeds fared reasonably well, with the notable exception of France's Marion Bartoli, whose up-and-down season continues to mystify observers who see tremendous talent but erratic temperament.

Bartoli gave up eight double faults in a straight sets loss to the resurgent Svetlana Kuznetsova of Russia 6-4, 6-4.


Top seed Victoria Azarekna got off to a slow start against Switzerland's Romina Oprandi before reeling off nine consecutive games and taking the match 6-2, 6-3.

"I felt like it was a little bit of a slow start for me - I started to go for my shots too much at the beginning," said the world number one. "Then I started to be more patient, work the points more, got more into the game and started to play much better. I'm really glad I could turn it around.

"She's a very tricky opponent," said Azarenka of Oprandi "I never want to underestimate my opponents. She's a very talented girl - and she's kind of a flashy player, a little bit. If you don't put enough pressure on her, if you don't put her in a situation she doesn't like, she will change the rhythm and go for her shots, and make you a little bit crazy on the court. So it was important to stay on top of her and not let her play the game she likes."

Few of the top names in action were troubled in their second round tests, although former world number one Caroline Wozniacki found herself facing set point in the opening first set tie break with the talented but at times uncontrolled Sorana Cirstea of Romania before gutting out a 7-6(7) win and sweeping the second set 6-0.

The tournament also continued with its odd share of retirements as both Simona Halep of Romania (against Ana Ivanovic) and Ekaterina Makarova of Russia (against Petra Kvitova) limped off before their matches had ended. The withdraws take the total amount of retirements for the tournament to six before the third round has even commenced.

Other day three winners included fourth seed Agnieszka Radwanska, sixth seed Sara Errani and eigth seed Samantha Stosur.

Thursday's line-up features Serena Williams taking on the younger Radwanska sister Urszula, Germany's giant killer Mona Barthel against Wozniacki and a potentially tricky match for Azarenka against the American Christina McHale.

Play beings at 3:30 local time with Agnieszka Radwanska against Ivanovic.