New world No.1 Aryna Sabalenka has overtaken Iga Swiatek in the WTA rankings due to a little-known rule — Casey Dellacqua makes the case for why the Australian Open champion deserves the mantle while The Sit-Down’s Viv Christie helps preview the WTA Finals. Analyst Simon Rea shines the data spotlight on rising superstar Mirra Andreeva and Stockholm champion Tommy Paul. And we preview the third instalment of the United Cup, kicking off the Australian summer of tennis just after Christmas.