Petrova, Ivanovic win Porsche openers

Eighth-seeded Russian Nadia Petrova and former world No. 1 Ana Ivanovic were among Tuesday's opening-round winners at the $795,000 Porsche Tennis Grand Prix.

The 2006 champion and 2008 Porsche runner-up Petrova got past German qualifier Dinah Pfizenmaier 7-6 (7-2), 6-4, while the former French Open titlist Ivanovic of Serbia whipped wild card and German crowd favorite Andrea Petkovic 6-3, 6-2 on the red clay at Porsche Arena.

Also on Day 1, German Sabine Lisicki erased Italian qualifier Nastassja Burnett 6-3, 6-4 and Croatian qualifier Mirjana Lucic-Baroni dismissed Russian Elena Vesnina 6-0, 6-4. Lucic-Baroni will meet second-seeded Australian Open runner-up Li Na of China in the round of 16.

First-round matches will come Wednesday for fifth-seeded former Wimbledon runner-up Petra Kvitova, sixth-seeded former U.S. Open champion Samantha Stosur, and seventh-seeded former world No. 1 and 2011 Porsche runner-up Caroline Wozniacki. The 2010 Stuttgart runner-up Stosur will battle former No. 1 and 2008 Porsche champion Jelena Jankovic.

This week's top seed is new Porsche global brand ambassador and reigning Stuttgart champion Maria Sharapova, who beat Victoria Azarenka in last year's marquee finale.

The 2013 Stuttgart champ will collect $130,000 and a new Porsche 911 Carrera.