Stan Wawrinka of Switzerland in action against Kevin Anderson of South Africa during the quarterfinals of the Rogers Cup Men’s Singles tennis tournament in Toronto, Canada, 29 July 2016. EPA/WARREN TODA

Venus Williams of the USA in action against Madison Keys of the USA during the third round of the Rogers Cup tennis tournament in Montreal, Canada, 28 July 2016. EPA/ANDRE PICHETTE

Milos Raonic of Canada in action against Jared Donaldson of the USA during the third round of the Rogers Cup Men’s Singles tennis tournament in Toronto, Canada, 28 July 2016. EPA/WARREN TODA

Radek Stepanek of the Czech Republic in action against Novak Djokovic of Serbia during the third round of the Rogers Cup Men’s Singles tennis tournament in Toronto, Canada, 28 July 2016. EPA/WARREN TODA

Svetlana Kuznetsova of Russia serves to Simona Halep of Romania during the quarterfinals of the Rogers Cup Women’s tennis tournament in Montreal, Canada, 29 July 2016. EPA/Andre Pissette