Semi-final places decided at WTA Tournament of Champions in Sofia
All four semi-final places at the Tournament of Champions were decided on the penultimate day of round robin matches.
Last Updated: 01/11/12 10:07pm
Caroline Wozniacki qualified as the winner of the Serdika Group after extending her perfect run at the tournament with a 3-6 7-6 (7-4) 6-4 victory over Daniela Hantuchova.
The result ensures the Dane finishes top of the group while Italy's Roberta Vinci will join her in the last four after thrashing Hsieh Su-wei 6-1 6-2.
Hsieh and Hantuchova have both lost two matches so far, rendering their clash on Friday a dead rubber.
In the Sredets Group, Nadia Petrova qualified for the semi-finals with a 3-6 7-6 (7-4) 6-3 win over Maria Kirilenko, whose subsequent withdrawal from the tournament handed a place in the last four to home favourite Tsvetana Pironkova.
Petrova came out on top after a hard-fought battle with fellow Russian Kirilenko which lasted two hours and 48 minutes.
Kirilenko was still well placed to reach the semi-finals but pulled out with a respiratory illness, meaning Pironkova qualifies as she holds the head-to-head tie-breaker over Zheng Jie.
Friday's three matches are not completely insignificant, however, as Petrova and Pironkova will face-off to determine who finishes top of the group, with the loser facing Wozniacki in the semi-finals.