The draw for the round robin stage of the season-ending WTA Championships was made in Turkey's largest city Istanbul on Sunday.

Li Na

The white group will feature Maria Sharapova (Russia), Victoria Azarenka (Belarus), Li Na (China) and Samantha Stosur (Australia) while the red group consists of Caroline Wozniacki (Denmark), Petra Kvitova (Czech Republic), Vera Zvonareva (Russia) and Agnieszka Radwanska (Poland).

The round robin stage will have two groups in the single's category with the top two from each group progressing to the semifinals.

France's Marion Bartoli and Germany's Andrea Petkovic will travel to Istanbul as singles alternates.

The competition will also feature the doubles teams of Kveta Peschke/Katarina Srebotnik, Liezel Huber/Lisa Raymond, Gisela Dulko/Flavia Pennetta and Vania King/Yaroslava Shvedova.

The WTA's year-end finale, to be held in Istanbul from Oct.25-30, will feature the world's top eight singles players and top four doubles teams competing for the coveted title and a share of the 5 million US dollars in prize money.