|Kvitova (above) will be up against Belarussian Azarenka for position of world number two in the finals[Reuters]
Wimbledon champion Petra Kvitova moved closer to the second biggest title of her career by beating US Open champion
Samantha Stosur here Saturday to reach the final of the WTA Championships.
But the incisive left-hander from the Czech Republic had to recover from a set down and from within one point of a break down in the second set against the determined Australian before winning 5-7, 6-3, 6-3.
Kvitova will finish the season as world number two if she goes on to win the title on Sunday, and at her best she looked well capable of it.
But she will be up against another in-form player, Victoria Azarenka, the tall and increasingly more dependable Belarussian who won 6-2, 6-3 against Vera Zvonareva, the former Wimbledon and US Open finalist from Russia.
Azarenka too can become world number two for the first time if she wins the WTA Championship title, but Kvitova will be slight favourite, not least because she won both their meetings this year.
Kvitova also had a worrying spell after establishing a 4-2 first set lead, during which unforced errors began to spray from her racket.
Stosur's morale levels rose visibly, she broke twice in three attempts to steal the first set, and came close to breaking again.
It wasn't long however before Kvitova improved. The essence of that was playing to her strengths and playing as far up the court as possible.
Although Stosur served her way spiritedly out of trouble to avoid going 1-4 down, she was unable to prevent Kvitova breaking through again in the ninth game and levelling at a set all.
Azarenka's win was more straightforward, and might have been more comfortable still, but for a couple of service game blips in the second set.
She struck the heavier drives in a match characterised by baseline exchanges. When Zvonareva found good angles and began to manoeuvre the ball around Azarenka had the physical capacity to run the ball down and contain her.
It was hard to believe that this was the player so disheartened by early season defeats, she considered quitting the game at the age of 22. She now contemplates the biggest title of her career.
Asked if she thought she could emulate Amelie Mauresmo by winning this title, and going on to win a Grand Slam title, Azarenka replied: "It's definitely gonna be a good learning experience to really, you know, be on the big stages winning one of the biggest tournaments.
"You know, I have played in some finals, and you know, a semi-final of a Grand Slam. I just take it as a learning experience, and next year it's gonna be next year."