Unbeaten Wozniacki rolls on in Bulgaria
Top seed Caroline Wozniacki confirmed her place in the semi-finals of the Tournament of Champions on Thursday, after completing her third successive victory of the group stage.
Wozniacki was made to work for her latest success in Sofia, however, dropping the first set - and surviving a second set tiebreak - before fighting back to defeat Daniela Hantuchova 3-6 7-6(4) 6-4.
In the competition's other group, Nadia Petrova is also through after overcoming Maria Kirilenko in a contest that went on for nearly three hours.
Indeed, the exertion proved too much for Kirilenko, who subsequently withdrew from the event with an upper respiratory illness that handed Tatiana Pironkova a place in the semi-finals of the competition - almost certainly against Wozniacki.
The contest between Petrova and Kirilenko was, in theory at least, to decide who would top the group - and the two players, locked at 4-4 from their eight previous meetings, played the contest as such. There was little to choose between them throughout, but Petrova eventually wrestled control of proceedings in the third stanza as she secured a 3-6 7-6(4) 6-3 triumph.
"This win for sure is going to give me some confidence," Petrova said. "She's the toughest opponent in the group and it was a very tight match, and now I have a 2-0 lead in the group - every little advantage helps here."
After withdrawing, Kirilenko said: "I'm very sorry that I cannot continue to play my matches here. It was such an honor to receive the wildcard ... unfortunately with this illness I can't finish the tournament as I'd have wished."
In the day's other match, Roberta Vinci defeated Su-Wei Hsieh 6-1 6-2.