A fan wearing a hat in the colours of the Romanian flag shows his support for Simona Halep of Romania during her match against Flavia Pennetta of Italy in round one of the singles round robin stage of the BNP Paribus WTA Finals 2015 held at the indoor stadium in Singapore, 25 October 2015. EPA/WALLACE WOON

Flavia Pennetta of Italy in action against Simona Halep of Romania during a match in round one of the singles round robin stage of the BNP Paribus WTA Finals 2015 held at the indoor stadium in Singapore, 25 October 2015. EPA/WALLACE WOON

Maria Sharapova of Russia in action against Agnieszka Radwanska of Poland during their Women’s singles round robin stage match of the BNP Paribus WTA Finals 2015 held at the indoor stadium in Singapore, 25 October 2015. EPA/WALLACE WOON

Agnieszka Radwanska of Poland in action against Maria Sharapova of Russia during a match in round one of the singles round robin stage of the BNP Paribas WTA Finals 2015 held at the indoor stadium in Singapore, 25 October 2015. EPA/WALLACE WOON

Maria Sharapova of Russia celebrates after winning her match against Agnieszka Radwanska of Poland in round one of the singles round robin stage of the BNP Paribas WTA Finals 2015 held at the indoor stadium in Singapore, 25 October 2015. EPA/WALLACE WOON