Petra Kvitova outlasted Victoria Azarenka Sunday, winning the season-ending WTA Championships in Turkey and assuring herself the world No. 2 position. The 21-year-old Czech gutted out a 7-5, 4-6, 6-3 victory in Istanbul, surviving a comeback try by Azarenka to grab her sixth title of the year. Kvitova has also won Wimbledon, Brisbane, Paris (indoors), Madrid and Linz this season, completing a break-out year. She will dislodge Maria Sharapova for second place in the year\'s final rankings. Fourth-seeded Azarenka was accurate on first-serves, putting 77 percent of them in play, but managed to win only 56 percent of those points while being broken five times. The Belarusian fell to 3-2 in title matches this season.