Kolkata, Sep 21 (IANS) Sandra Kloesel of Germany got the better of Russian Galina Voskoboeva 7-6 (7-5), 5-7, 6-4 Wednesday to set up a date with Indian favourite Sania Mirza in the next round of Sunfeast Open played here.

The German managed to hold her nerves after being stretched to the limit by Voskoboeva in the match that lasted almost three hours. The big-serving Russian had 18 aces.

Meanwhile, world number nine Martina Hingis of Switzerland trounced former Israeli army cadet Tzipora Obziler 6-2, 7-5 to set up a quarter-final facing against Tamarine Tanasugarn of Thailand.

In the Kloesel-Voskoboeva match, the first set ended on an even note with the two trading breaks and playing out a close tiebreaker. In the second, Kloesel raced to a 3-0 lead, but the Russian broke her service in the fifth and held the sixth to draw level. A decisive break in the 11th game gave the Russian the set.

At one-set all and with games going with serves Klosel got the crucial break in the 10th game to win the set 6-4.

"I just wanted to hang on there. She was serving really well and I knew I just needed one break to do the trick and I did that to take the match," Klosel said after the match.

Hingis had to slog it out with the 33-year-old Israeli and the first set that she won 6-2 was tougher than what the scoreline predicted.

It also showed the difference between a champion and a mere aspirant.

"I am looking forward to playing Tamarine. I played her twice and was winner on both occasions. I hope to continue the same way on Friday when I meet her," Hingis later said.

The second set was a sheer thriller, with breaks being traded and fortunes fluctuating. After both the players tied at 4-4, the ninth game was a marathon with five deuces being fought before Obziler held serve.

Hingis held serve in the tenth game and suddenly three deuces later she was up 6-5 and served for the match. Two weak backhand returns had done Obziler in.

Tanasugarn earlier became the first player to qualify for the quarterfinals.

Tanasugarn played her trademark baseline game to beat Abigail Spears of the US 2-6, 6-3, 6-2.

"She was hitting winner after winner and I just could not be in the game," Tanasugarn said later. But from the second set onwards, she started playing more rallies and as she started returning winners the American's game fell apart.

"I made her play more rallies and that did the trick. I wanted her to destroy herself and she did exactly that," she said.

The third set was easier for her as she won consecutive breaks in the sixth and eighth games to clinch the deal.

Tanasugarn had briefly partnered Maria Sharapova and won two doubles titles with her in 2003.

In the doubles US-based Sunitha Rao and Casey Delacqua of Australia defeated the Thai-Taipei pair of Tanasugarn and Chia-Jung Chuang 6-2, 4-6, 7-6 (8-6).

Meanwhile, Rushmi Chakravarthy's campaign at the Tier III meet came to an end. The Indian, along with partner Sandy Gumulya of Indonesia, went down 1-6, 0-6 to the Czech-Indonesian pair of Hana Sromova and Angelique Widjaja.

In another doubles match, Akgul Amanmuradova retired with a right ankle sprain as she and her partner Iroda Tulyaganova conceded the tie 6-7 (6-8), 7-5, 0-3 against the Ukrainian pair Yulia Beygelzimer and Yuliana Fedak.