‘Kokkinakis banged your girlfriend. Sorry to tell you that, mate,’ the Australian tennis player Nick Kyrgios remarked to his opponent Stan Wawrinka during a match in Montreal in 2015. He was referring to Thanasi Kokkinakis, who had partnered Wawrinka’s girlfriend in mixed doubles. After Kyrgios’s remark, Wawrinka’s game went to pieces, and he soon retired from the match with a ‘back problem’.