体坛英语新闻：Kvtiova, Wosniacki, Stosur power to wins on day 1 of WTA season-ending championships in Istan

ISTANBUL, Oct. 25 (Xinhua) -- Petra Kvitova, Carline Wosniacki and Samantha Stosur on Wednesday secured their first wins in the round robin stage of the season-ending WTA Championships in Turkey's largest city Istanbul.

In the first match of the evening, Kvitova beat Vera Zvonareva 6-2, 6-4 in straight sets to get off the mark with a win.

The second match saw Wosniacki, the world No. 1, had to dig deep to recover from a set down to overcome Agnieszka Radwanska 5-7, 6-2, 6-4.

The final game of the evening saw Stosur beat Maria Sharapova 6-1, 7-5 in straight sets.

The WTA's year-end finale, being held at Istanbul's Sinan Erdem Arena 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 round robin stage consists of two groups in the single' s category with the top two from each group progressing to the semifinals.

The White group features Maria Sharapova (Russia), Victoria Azarenka (Belarus), Li Na (China) and Samantha Stosur (Australia) while the Red group features Caroline Wozniacki (Denmark), Petra Kvitova (Czech Republic), Vera Zvonareva (Russia) and Agnieszka Radwanska (Poland).

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.

France's Marion Bartoli and Germany's Andrea Petkovic are also in Istanbul as singles alternates.