Love him or hate him, the flawed genius that is Nick Kyrgios is one of the most polarising figures on the tennis circuit but he, at least, is "comfortable" with himself. The enigmatic Australian stunned the tennis world as a 19-year-old in 2014 when he beat then world number one Rafael Nadal on his way to the Wimbledon quarter-finals. But frequent tantrums and fines have overshadowed his undoubted talent and he has never achieved a better finish at a Grand Slam. Eight years on, Kyrgios again finds himself in the last eight at Wimbledon and this time with a serious chance to realise his full potential.