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,

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,