Shock exit out of Stuttgart for Ivanovic

Wild-card Mona Barthel was delighted by her shock first-round win over former idol and ex-world number one Ana Ivanovic at Stuttgart's clay-court WTA tournament on Wednesday.

The 21-year-old German blasted down 11 aces to out-muscle Serbia's Ivanovic, ranked 15th in the world, in straight sets for a 7-5, 7-6 (7/4) victory and will now face seventh-seed Marion Bartoli of France in the second round.

"There was something special, because Ana used to be a bit of a role model for me," said Barthel, ranked 35th in the world.

"I was still at school when she won the (2008) French Open and I watched it on television.

"At that time all this was a long, long way off for me."

Ivanovic has struggled for form since she rose to world number one nearly four years ago following victory at Roland Garros.

Her best recent form has been at the US Open when she reached the fourth round in both 2010 and 2011.

She started her semi-final against Maria Sharapova at Indian Wells at the start of March, but was forced to retire with a hip injury.

In contrast, Barthel is part of a batch of promising female tennis players emerging from Germany having won the Hobart WTA tournament in January.

She went on to reach the third round at the Australian Open where she lost to eventual winnner Victoria Azarenka, the current world number one.

Meanwhile, fourth-seed Agnieszka Radwanska of Poland booked her place in the quarter-finals when she beat qualifier Greta Arn of Hungary 6-3, 6-4 in their second round match.

In the day's other ties here, Russian tennis diva and world number two Maria Sharapova makes her debut against French qualifier Alize Cornet on Wednesday evening in the second round.

There will be a battle of the former world number ones later when Denmark's Caroline Wozniacki, the sixth-seed here, takes on Serbia's Jelena Jankovic with the winner to face Germany's Angelique Kerber in the second round.