The duo of Sania Mirza and Bethanie Mattek-Sands have stormed into the final of the WTA Porsche Tennis Grand Prix in Stuttgart, Germany. The unseeded Indo-American pair carved out a 6-4 7-5 win over local favourite combination of Angelique Kerber and Andrea Petkovic in the semifinals in one hour and 31 minutes.They will next clash with giant-killers and another local favourites Sabine Lisicki and Mona Barthel, who got the better of Darija Jurak and Katalin Marosi 6-3 6-4 in the other semifinal of the clay court event.Sania and Bethanie had won Brisbane and Dubai events early in the year.