Agnieszka Radwanska claimed her maiden WTA Finals title with a 6-2, 4-6, 6-3 victory over Czech Petra Kvitova in an absorbing encounter at the Singapore Indoor Stadium today.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.