Agnieszka Radwanska has admitted that "it means everything" to have won the WTA Championships.

The 26-year-old, who is yet to lift one of the four Grand Slam titles, overcome Petra Kvitova 6-2 4-6 6-3 in just over two hours in Singapore this afternoon to record what was the biggest victory of her career to date.

"A few weeks ago I didn't even know I'd have a chance to be here, and there you go," the Pole said during her post-match interview.

"It's just an incredible day for me. It means everything and it couldn't be any better. I think that was the biggest day in my life."

Radwanska has now won 17 WTA titles over the course of her career.