Novak Djokovic has weighed in on tennis's high-profile doping cases and criticized what he perceives as double standards in the sport.

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Novak Djokovic says Nick Kyrgios has 'spoken well' about Jannik Sinner 's doping case after the Aussie labelled the scandal 'disgusting' for tennis.

Novak Djokovic has spoken out about World No.1 Jannik Sinner’s ongoing doping case, backing doubles partner Nick Kyrgios and labelling the situation as ‘frustrating’. Djokovic and Kyrgios are both currently in Brisbane for the Australian Open warm-up event, where they will be playing singles and doubles together for the first time.

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.

Novak Djokovic expressed his frustration at being "kept in the dark" about world number one Jannik Sinner's doping case, saying in Brisbane on Sunday that it was not a good look for tennis.

Nick Kyrgios has said the doping charges against Jannik Sinner and Iga Swiatek are “disgusting for our sport” as he prepares to make his long-awaited return to tennis.