Novak Djokovic told reporters in Australia that he "is not questioning whether Jannik Sinner took the banned substance intentionally or not" but noted that he is "really frustrated" with the fact that no one knew anything about the Italian and Iga Swiatek until the investigation in their doping cases concluded.

On the eve of his return to the court, Novak Djokovic has weighed in on the tennis’ high profile doping cases and criticized what he perceives as double standards in the sport.

Nick Kyrgios continues to add to his digs of World No.1 Jannik Sinner reposting a mocked up Christmas image of the pair and adding his own comment. Kyrgios has long been at the throat of Sinner over his positive test for substance Clostebol in which he escaped suspension twice.