SINGAPORE - OCTOBER 18:  (L-R) Caroline Wozniacki of Denmark, Agnieszka Radwanska of Poland, Petra Kvitova of Czech Republic, Serena Williams of USA, Maria Sharapova of Russia, Ana Ivanovic of Serbia, Eugenie Bouchard of Canada and Simona Halep of Romania pose for a photo at the Gardens by the Bay during previews for the WTA Finals at Singapore Sports Hub on October 18, 2014 in Singapore.  (Photo by Clive Brunskill/Getty Images)