- Petra Kvitova defeats Victoria Azarenka in the final of the WTA Tour Championships
- The Czech wins 7-5 4-6 6-3 to add the title to her Wimbledon crown earlier this season
- Kvitova's sixth title of the year moves her up to second place in the world rankings
Wimbledon champion Petra Kvitova out-fought Victoria Azarenka in three tough sets to win the season-ending WTA Tour Championships in Istanbul.
The third seed completed a remarkable year with a 7-5 4-6 6-3 success over nearly two-and-a-half hours, becoming only the third woman to win the tournament on her first visit.
The 21-year-old Czech has been totally dominant this week, winning all three of her group games before recovering from a set down to beat U.S. Open champion Sam Stosur in the semifinals.
And this success means she now moves up to second place behind Caroline Wozniaki in the world rankings, after starting 2011 down in 30th position.
Kvitova told the official WTA Tour website: "It was unbelievable tennis. We were both really fighting.
"Every game and every set was very close. Maybe I played better on the important points in the match but we both played some of our best here in Istanbul -- it was a final, so why not!"
And asked how this victory compared to her Wimbledon success, Kvitova told reporters: "Winning a grand slam was a very big step. I don't know how it will be going home this time, but I think it will be similar.
"I will be world number two now and next season will be different. I may be the favorite all the time, and we will have to see how I cope with that."
Third seed Azarenka of Belarus was gracious in defeat, adding: "It's hard to lose, but I'm glad I lost to such a champion who deserved to win this week.
"Petra was amazing today. She really did a great job because I gave it my all. The crowd kept me fighting all the way through -- they have been amazing all week.
The match turned in the opening game of the final set when Azarenka squandered two break points on the Kvitova serve.
She then took advantage of Azarenka's disappointment by making the crucial break of serve in the next game, taking the first chance she had to achieve it.
It was Kvitova's sixth WTA Tour title of the season and in securing victory she became the first Czech to lift the coveted trophy since Jana Novotna in 1997.
Meanwhile, Jo-Wilfried Tsonga has moved up to seventh place in the race to reach the climax to the men's tennis season with a hard-fought victory over Juan Martin Del Potro in the final of the Austrian Open in Vienna.
The top-seeded Frenchman beat the Argentine second seed 6-7 6-3 6-4 to put himself in line for a place in the ATP Tour finals in London next month.
Del Potro is up to 11th place in the points chase and also still has a chance of reaching London, with more points to be had at next week's Valencia Open.