In Stuttgart Grand Prix final, Angelique Kerber defeated qualifier Laura Siegemund in the tournament's first all-German final. Kerber beat Siegemund in straight sets 6-4, 6-0.Yesterday Siegemund caused a sensation, knocking out top seed and world number two Agnieszka Radwanska in straight sets to reach the Stuttgart Grand Prix final.Kerber ousted fifth seed Petra Kvitova 6-4, 4-6, 6-2 in the semis.