Roger Federer says there are still questions to be answered about Jannik Sinner avoiding a suspension after failing two anti-doping tests.
Jannik Sinner set up a blockbusting US Open quarter-final with Daniil Medvedev in a repeat of the Australian Open final.
Jannik Sinner avoided becoming the third big-name casualty at the US Open in three days with a straight-set victory on Saturday.
World number one Jannik Sinner is ready for any criticism coming his way from player-turned-presenter Nick Kyrgios at the US Open.
World number one Jannik Sinner admits he has endured an icy reception from players at the US Open following his failed anti-doping tests controversy.
World number one Jannik Sinner insists he did not get preferential treatment after avoiding a ban for two failed anti-doping tests and maintains he is "clean".