Petra Kvitova and Victoria Azarenka on Saturday booked their places in the final of the season-ending TEB BNP Paribas WTA Championships in Turkey\'s largest city Istanbul.Kvitova fought back from a set down to beat Samantha Stosur 5-7, 6-3, 6-3 in the first single\'s semifinal of the day.Azarenka overcame her opponent Vera Zvonereva in straight sets 6-2, 6-3 to progress to the finals.Meanwhile, the semifinals in the double\'s category was also played Saturday with the pairing of Peschke/Srebotnik making the final by beating King/Shvedova 6-3, 6-4.The other semifinal saw the pairing of Huber/Raymond overcome Dulko/Pennetta 4-6, 6-3, 10-7 to reach Sunday\'s final.The WTA\'s year-end finale, being held at Istanbul\'s Sinan Erdem Dome on indoor hard courts from Oct. 25-30, features the world\'s top eight singles players and top four doubles teams competing for the coveted title and a share of the 5 million U.S. dollars in prize money.The White group featured Maria Sharapova (Russia), Victoria Azarenka (Belarus), Li Na (China) and Samantha Stosur (Australia) while the Red group featured Caroline Wozniacki (Denmark), Petra Kvitova (Czech Republic), Vera Zvonareva (Russia) and Agnieszka Radwanska (Poland).The competition also featured the doubles teams of Kveta Peschke/Katarina Srebotnik, Liezel Huber/Lisa Raymond, Gisela Dulko/Flavia Pennetta and Vania King/Yaroslava Shvedova. France\'s Marion Bartoli and Germany\'s Andrea Petkovic were also in Istanbul as singles alternates.