Stuttgart  - Russian seeds Svetlana Kuznetsova and Nadia Petrova posted hard-fought three-set victories on Wednesday to reach the second round of the Porsche Grand Prix.

The fifth-seeded Kuznetsova needed five match points to defeat German qualifier Andrea Petovic 6-4, 5-7, 6-1 in 2 hours 6 minutes.

Petrova, the sixth-seeded 2006 champion and 2008 runner-up, was on court 20 minutes longer in her victory against Zheng Jie of China 6- 4, 5-7, 6-4.

Defending champion Jelena Jankovic of Serbia was due to play later Wednesday against Slovakia's Dominika Cibulkova.

Kuznetsova, a three-time semi-finalist in Stuttgart, was in danger of going out in the first round the second straight year, against the 143rd-ranked Petkovic who is aiming to return into the top 100 after being sidelined for eight months last year with a knee injury.

Kuznetsova won the first set after some late hiccups, but then double faulted to give Petkovic a 6-5 edge in the second as the German squared the sets with an ace a game later.

But Kuznetsova regrouped swiftly and raced off to a 5-0 lead. She wasted four match points in the next game but then succeeded on her fifth opportunity when Petkovic hit a backhand wide.

"I had too many ups and downs, especially in the second set. I am quite disappointed with myself," said Kuznetsova.

Petkovic said: "I didn't have the experience and the patience at the start of the third set. She was there when it mattered."(dpa)