Sania Mirza squandered one set advantage to go down fighting against fourth seed Jelena Jankovic of Serbia 6-4, 3-6, 4-6 to crash out of the USD 1,500,000 Dubai Tennis Championships here on Tuesday.

Sania, who pulled off a 7-6(5), 6-2 win over Russian qualifier Vera Dushevina in the opening round, found her touch early in the second round match, sending down her trademark forehand volleys to unsettle her higher ranked rival to go one set up.

But, the Hyderabadi failed to maintain her momentum, allowing her Serbian opponent to claw back into the match which was also made easier by some unforced errors by the 32nd ranked Indian.

Jankovic tightened the screw and won the second set before fighting off a strong challenge from the Indian to advance into the next round of the WTA Tier II event.

Venus stunned

Top seed Venus Williams was stunned in the first round of the Memphis International by Czech qualifier Petra Kvitova on Tuesday, the 17-year-old left-hander rallying to defeat the defending champion 2-6, 6-4 6-3, reports Reuters from New York.

The American world number eight eased through the opening set before her opponent, ranked 135 places below Williams, rallied to take the final two sets for the biggest victory of her young career.

In another upset, second seeded Frenchwoman Tatiana Golovin was beaten 6-4, 6-4 by American world number 148 Bethanie Mattek.

"This year I've actually been playing pretty good," Mattek said.

"I was sick in Australia and I played an awesome match in Chile (in a loss to Jelena Kostenic). I had match points there but it just didn't go my way."

The American raced to a 5-1 lead in the first set and was never threatened.

Third seed Shahar Peer was able to advance, however, the Israeli easing to a 6-2, 6-1 victory over American Ahsha Rolle, joining sixth seeded Caroline Wozniacki in the second round after the Dane dumped Venezuela's Milagros Sequera 6-0, 6-2.

In second-round matches, Olga Govortsov of Belarus rallied to defeat Renata Voracova of the Czech Republic 4-6, 6-4, 7-6 and seventh seeded Sophia Arvidsson of Sweden battled to a 1-6, 7-5, 6-3 win over Canada's Stephanie Dubois.

Sunitha bows out

Meanwhile,  India's Sunitha Rao and her doubles partner Sophie Lefevre of France went down to American pair Carly Gullickson and Shenay Perry 0-6, 4-6 in the first round of the the doubles.