Novak Djokovic and Andy Murray chatted mid-match thanks to the new Australian Open coaches’ box

Murray pantomimed the swing of a two-handed backhand. Djokovic took it all in, then responded. The scene was remarkable because of the new — and “a little bit strange,” Djokovic said Monday night — relationship between these two stars of their sport, yes, but also because that face-to-face conversation was able to happen at all in the middle of a Grand Slam match.