An emotional Agnieszka Radwanska claimed her maiden WTA Finals title with a roller-coaster 6-2 4-6 6-3 victory over Czech Petra Kvitova in an absorbing encounter at a packed Singapore Indoor Stadium on Sunday.
Playing a first final in her seventh appearance at the season-ending event, the sixth-ranked Pole also created history by becoming the first woman to lift the title after completing round-robin play with a 1-2 record.
"A few weeks ago I didn't even know I would be here," a tearful Radwanska said in a courtside interview.
"I was doing the right thing in the important moments of a really close match, I had my chances in the second set but it doesn't really matter how I won," the Pole added.
In stark contrast to her semi-final victory over Maria Sharapova, Kvitova made a lacklustre start to the match with a sloppy opening service game, handing her opponent an immediate break as she got off to the worst possible start.
The Czech appeared a little more animated in the second game and despite working a few openings, poor shot selection and a string of unforced errors enabled the world number six to survive the threat and move 2-0 ahead.
The double Wimbledon champion finally got on the scoreboard in the third game thanks to a pair of aces but unable to make any inroads on the Radwanska serve, the Czech recorded her third double-fault in as many games to cough up yet another break.
Exuding confidence, Radwanska breezed through her next service game and was able to wrap up a dominant set in 33 minutes with another routine hold.
Radwanska carried that momentum into the first game of the second set, running down everything and breaking the Czech with an unreturnable backhand volley at the net and consolidating her advantage with a solid hold to win her third game in a row.
Kvitova, who continues to battle mononucleosis, stopped the rot to claim her first game of the second set, screeching in delight at a forehand winner as she attempted to stir herself into action.
Her efforts bore fruit three games later when the powerful left-hander forged her first break point of the contest and levelled at 3-3 with a booming crosscourt forehand winner.
An easy hold put her ahead for the first time in the set and suddenly the crowd had a contest to watch after Radwanska's march to victory was halted and Kvitova completed the comeback with a second consecutive break to set up a decider.
Kvitova was trying to keep the points short, grimacing in pain and clutching her bandaged right thigh after each rally as the pair traded a pair of breaks apiece to remain deadlocked at 3-3 in the decider.
Radwanska dug deep once more and forged another break before finally holding to leave her one game away from the biggest victory of her career, ending Kvitova's resistance on her first match point when the Czech committed her 53rd unforced error.
"It means everything to me... in my first final, I get my first win so it couldn't be any better," the 26-year-old Pole added.
In the final of the doubles event, Martina Hingis and Sania Mirza claimed their ninth title of their first season together with a 6-0 6-3 victory over Spain's Garbine Muguruza and Carla Suarez Navarro.