WARSAW, May 4: Venus Williams hung on for a dramatic 4-6 7-5 6-4 victory over Martina Hingis on Thursday to reach the quarterfinals of the Warsaw Cup.

Hingis had every opportunity to win the two hour 38-minute battle and the nightmare of her struggle to get the better of the Williams sisters, which many in the game believe played a part in her retirement in 2002.

A strong wind prevented both players from producing their best tennis and Swiss Hingis came within two points of victory over the Wimbledon champion at 5-4 in the second set.

Williams was thrilled to have won such a challenging match so early in her comeback. The seventh seed is playing this week for the first time in over three months.

Although Williams held for 5-5 in the second set and conceded just two points in the remainder of the set, cramps struck her when she had broken to lead 1-0 in the third set.

She received treatment at 1-1 after dropping her serve, again after breaking to love to lead 2-1, and once more when leading 3-2.

When Hingis, like Williams a former world number one, broke her to love to level at 3-3 it appeared as if the American's challenge was over.

Barely able to lift off to serve, or to move, she relied on hitting out as hard as she could at any ball that came within reach.

The power of her opponent forced Hingis into errors, and after an exchange of breaks to 4-4, a forced backhand error gave Williams another break for 5-4 and she served out for the match.

Results (second round matches):

Anna Chakvetadze (Russia) beat 9-Daniela Hantuchova (Slovakia) 6-4 6-3; Ana Ivanovic (Serbia and Montenegro) beat 2-Patty Schnyder (Switzerland) 6-3 6-2; 7-Venus Williams (U.S.) beat Martina Hingis (Switzerland) 4-6 7-5 6-4; 4-Svetlana Kuznetsova (Russia) beat Tsvetana Pironkova (Bulgaria) 6-3 6-1

Estoril results

Men's singles (second round): Frederico Gil (Portugal) beat 5-Dmitry Tursunov (Russia) 4-6 6-4 6-1; Guillermo Garcia-Lopez (Spain) beat Carlos Berlocq (Argentina) 6-7(11) 7-5 7-6(5)

Women's singles: Jie Zheng (China) beat Laura Pous (Spain) 6-2 2-6 6-3 ; Na Li (China) beat Katerina Bohmova (Czech Republic) 6-1 6-0; Emilie Loit (France) beat Natalia Gussoni (Argentina) 6-2 6-2; Lourdes Dominguez (Spain) beat Kaia Kanepi (Estonia) 6-1 6-4 —Agencies