Novak Djokovic sought assistance from a trainer for some trouble breathing Friday night, and went back-and-forth with one particularly loud spectator, but when the ball was in play at the Australian Open against Tomas Machac,

Count Novak Djokovic as being in Danielle Collins’ corner. He thinks her response to booing fans at the Australian Open was absolutely fine — which should come as no surprise, given the way Djokovic gets into back-and-forths with hecklers at his matches,