Agnieszka Radwanska's defence of her WTA Finals crown has got off to a losing start courtesy of a three-set defeat to Svetlana Kuznetsova in Singapore this evening.

Kuznetsova recovered from match point to win 7-5 1-6 7-5 in the opening white group fixture, eventually coming through in just under three hours.

It was Radwanska who got off to the more encouraging start, breaking in the fourth game and quickly establishing a 4-1 lead.

However, Kuznetsova, who only sealed her place in the season-ending tournament at the weekend, won six of the next seven games to take control of the contest, breaking twice before wrapping the opener up with her third set point.

Radwanska responded strongly, however, matching Kuznetsova's run of six wins from seven games in a dominant second set to take it 6-1 in less than 40 minutes.

The Pole made a quick start to the deciding set too, breaking in the very first game on her way into a 2-0 lead.

Kuznetsova levelled things up again against the serve in the fourth game, but Radwanska responded immediately by breaking back and establishing a 4-2 lead.

Once again the Russian fought back to make it 4-4, only to lose serve in the next game yet again to leave Radwanska serving for the match.

The world number three moved to match point in the 10th game of the set, but Kuznetsova showed her fighting spirit to battle back and make it three breaks apiece in a topsy-turvy decider.

That proved to be the first of three consecutive games won by Kuznetsova as she eventually wrapped up a thrilling victory with her third match point.