Former world number one Martina Hingis [ Images ] was knocked out in the third round of the German Open on Thursday, losing 6-4, 6-0 to fellow Swiss Patty Schnyder [ Images ].

Hingis was clearly struggling with a back injury and was broken seven times by Schnyder in a match interrupted several times by rain.

The five-times Grand Slam winner said she had considered retiring from Thursday's match and could skip next week's Italian Open if she failed to regain her fitness.

"Patty was very solid -- and smart because she knows I have that little (injury)," Hingis said at a news conference. "She was patient and it was a good match for her."

The persistent rain meant world number one and top seed Justine Henin [ Images ] was unable to play her third-round tie against unseeded Maria Elena Camerin.

If Henin defeats the Italian she will face Jelena Jankovic [ Images ]. The Serbian fifth seed went through after China's Peng Shuai [ Images ] was forced to retire leading 3-2 in the third set.

Wimbledon [ Images ] champion Amelie Mauresmo [ Images ], back after a two-month layoff, was up 6-2, 1-1 against unseeded Ukranian Julia Vakulenko when their match was suspended as darkness fell over the Steffi Graf [ Images ] stadium.

The winner of that match will play Dinara Safina [ Images ] in the quarters after the Russian eighth seed overcame Lucie Safarova [ Images ] of the Czech Republic 3-6, 6-3, 6-2.

Defending champion Nadia Petrova [ Images ] brushed aside fellow Muscovite Elena Dementieva [ Images ] 6-3, 6-3.

The seventh seed broke Dementieva four times and will play another Russian, third seed Svetlana Kuznetsova [ Images ], for a place in the last four.

Kuznetsova had a comfortable 6-3, 6-2 win over unseeded German Martina Mueller, ending hopes of a local success at the claycourt event.

Serbian teenager Ana Ivanovic [ Images ] also went through. The number 12 seed was leading Alona Bondarenko 6-3, 5-0 when the Ukrainian sprained her ankle and retired. Ivanovic will play Schnyder in the quarters.