Belinda Bencic of OUE Singapore Slammers in action against Agnieszka Radwanska of Micromax Indian Aces during their match of the International Premier Tennis League (IPTL) at Dubai Duty Free Tennis Stadium in Dubai, United Arab Emirates on 16 December 2015. EPA/ALI HAIDER

Andy Murray of OUE Singapore Slammers in action against Bernard Tomic of Micromax Indian Aces during their match of the International Premier Tennis League (IPTL) at Dubai Duty Free Tennis Stadium in Dubai, United Arab Emirates on 16 December 2015. EPA/ALI HAIDER

Czech Karolina Pliskova (L) and German Dustin Brown (R) of of the OUE Singapore Slammers high five while in action against Roger Federer and Kristina Mladenovic of the Obi UAE Royals during their match at the International Premier Tennis League (IPTL) held at the indoor stadium in Singapore, 18 December 2015. EPA/WALLACE WOON

Czech Karolina Pliskova of the OUE Singapore Slammers in action against Kristina Mladenovic of the Obi UAE Royals during their match at the International Premier Tennis League (IPTL) held at the indoor stadium in Singapore, 18 December 2015. EPA/WALLACE WOON

Swiss Stan Wawrinka of the OUE Singapore Slammers in action against Roger Federer of the Obi UAE Royals during their match at the International Premier Tennis League (IPTL) held at the indoor stadium in Singapore, 18 December 2015. EPA/WALLACE WOON