Andy Murray of Britain in action against Nick Kyrgios of Australia during their men’s singles match between Australia Green and Great Britain in session 8 of the Hopman Cup tennis tournament at the Perth Arena in Perth, Australia, 06 January 2016. EPA/TONY MCDONOUGH

Sabine Lisicki for Germany during the mixed doubles match between France and Germany in session 7 on day 4 of the Hopman Cup at the Perth Arena, Wednesday, January 06, 2016. Sabine Lisicki and Alexander Zverev (not pictured) won the match. EPA/TONY MCDONOUGH

Alexander Zverev for Germany returns against Kenny De Schepper for France during the men’s match between France and Germany in session 7 on day 4 of the Hopman Cup at the Perth Arena in Perth, Australia, 06 January 2016. EPA/TONY MCDONOUGH

Lleyton Hewitt of Australia Gold returns the ball during the men’s match against the United States of America in session 6 on day 3 of the Hopman Cup at the Perth Arena, Perth, Australia, 05 January 2016. EPA/TONY MCDONOUGH

Jack Sock of the United States returns the ball during the men’s match between the United States of America and Australia Gold in session 6 on day 3 of the Hopman Cup at the Perth Arena, Perth, Australia, 05 January 2016. EPA/TONY MCDONOUGH