Wozniacki, Kvitova serve up wins at the WTA finals

Top-ranked Caroline Wozniacki rallied to defeat Agnieszka Radwanska of Poland 5-7, 6-2, 6-4 Tuesday in their opening round-robin match at the WTA Championships. (AP)

Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Petra Kvitova of Czech Republic serves to Vera Zvonareva of Russia(not pictured) during their WTA tennis championships match in Istanbul, on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)
Caroline Wozniacki of Denmark hits a return to Agnieszka Radwanska of Poland during their WTA tennis championships match in Istanbul on October 25, 2011. AFP PHOTO/BULENT KILIC (Photo credit should read BULENT KILIC/AFP/Getty Images)

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