Since August, Kyrgios has injected himself into Jannik Sinner's doping controversy by commenting so much about it online.

Their knowledge and dedication inspire me to work harder than ever, and I’m ready to put in the hard work," the Pole said.

Andy Murray turned down the opportunity to work with top players on both the ATP and WTA tours before becoming Novak Djokovic’s coach, according to Andy Roddick. Roddick revealed Murray was approached ...