Intro:

There were wins for Poland's Agnieszka Radwanska and Mona Barthel of Germany on day two at the Porsche Grand Prix in Stuttgart, Germany on Wednesday.

Script:

Ana Ivanovic was the strong favourite as she took to the court in Stuttgart to face Mona Barthel in the first round of the WTA Porsche Grand Prix on Wednesday.

But it was wildcard Barthel who sealed the first set 7-5.

Former world number one Ivanovic took the second set to a tie-break but her German opponent delighted the home support as she completed a surprise straight sets win to set up a quarter-final tie with Marion Bartoli.

Agnieszka Radwanska will join Barthel in the last eight after the fourth seed as she beat qualifier Greta Arn of Hungary.

The Polish 23-year-old clinched the first set 6-3.

Radwanska is in form after her recent victory in Miami and she wrapped up a 6-3, 6-4 win.

Radwanska will face either Li Na or Akgul Amanmuradova for a place in the semi-finals.