Serbia's Ana Ivanovic defeated Andrea Petkovic of Germany 6-3, 6-2 Tuesday in the first round of the Porsche Tennis Grand Prix.
Ivanovic needed just under 73 minutes to dispatch the 25-year-old Petkovic, who is struggling to regain her form after injury setbacks.
''I'm really annoyed with myself for making so many little mistakes,'' said Petkovic, who has dropped from ninth to 131st in the rankings. ''I had the feeling that I improved certain parts of my game in training. But then the consistency wasn't there on the court and that's simply annoying.''
The eighth-seeded Nadia Petrova of Russia avoided an upset by beating 21-year-old Dinah Pfizenmaier of Germany 7-6 (2), 6-4. Mirjana Lucic-Baroni of Croatia defeated another Russian, Elena Vesnina, 6-0, 6-4.
Germany's Sabine Lisicki defeated Nastassja Burnett of Italy 6-3, 6-4 in the late match.
