Wawrinka retires after a heated match in which the first two sets were tight and evenly matched. The third set was going fast towards Kyrgios and at 4-0 in his favour Wawrinka retires. Or was it really a back injury….Kyrgios was verbally abusing Wawrinka as well in this match, mentioning his current girlfriend tennis player Vekic. Kyrgios was clearly overheard telling Wawrinka during the match that his fellow Australian tennis player and friend Kokkinakis had banged his girlfriend: