Stars of women 's tennis put on their glad rags to attend the Porsche Grand Prix Tennis opening ceremony in Stuttgart on Monday . Defending champion Maria Sharapova was joined by players including Ana Ivanovic , Caroline Wozniacki , Sabine Lisicki , and Angelique Kerber ahead of their opening matches at the clay court tournament . The ladies were dressed glamorously as they posed for pictures at the Porsche Arena accompanied by a group of school children . Ana Ivanovic ( L-R ) , Sabine Lisicki , Angelique Kerber , Caroline Wozniacki and Maria Sharapova strike a pose . Ivanovic speaks to Wozniacki ( right ) during the opening ceremony of the Porsche Grand Prix Tennis event . The women 's tennis stars wave to the crowd ahead of their games at the clay court tournament in Stuttgart . World No 1 Serena Williams was the the highest profile absentee , admitting she was not ready for the clay court season after struggling to beat Sara Errani as the USA crashed out of the Fed Cup to Italy last week . ' I 'm totally not as ready for the claycourt season as I thought I was . Now I 'm in the mindset of , 'You know what , I 'm not on hard court . ' I 'm playing like I 'm on hard court and I 'm not , ' said Williams afterwards . 'So I have to play and be ready to hit a thousand shots if necessary . ' Meanwhile , the Stuttgart event could decide who is ranked second in the world with Simona Halep close to overtaking Sharapova in the WTA list . The Russian needs to reach the semi finals at least to retain her current ranking while Halep will move up a spot if she can better the No 1 seed 's progress . Ivanovic is escorted by a young mascot onto the court at the Porsche Arena . Sharapova ( right ) is top seed at the event she has won for the last three consecutive years . Local favourite Lisicki waves to the crowd as she takes the court with a young Germany fan . Wozniacki speaks to the media before getting her singles campaign underway . However , Sharapova , who has won the Stuttgart tournament for the last three years , is confident of hold on to her ranking . 'Despite everything , it 's always a nice feeling to come back to an event where you 've had a really good record . where you 've had some great matches , great memories , ' Sharapova told the WTA website . 'Some of the best matches of my career have been played on that court . But every year you come back to a tournament you start from the very beginning , and that 's what I 'll be doing this year to try and defend my title . ' Veterans Andre Agassi ( left ) and Thomas Muster staged an exhibition match before the tournament started .
Women 's tennis stars attended opening ceremony of Porsche Grand Prix . Maria Sharapova , Caroline Wozniacki , Sabine Lisicki , Angelique Kerber and Ana Ivanovic were among the players on show . With Serena Williams missing , Simona Halep could overtake three times winner Sharapova as world No 2 .