The 37-year-old Serbian great's upper left leg was again heavily taped after he hurt it in the quarter-finals and he called time after going down 7-6 (7/5).
Either way Djokovic and Australia remains an epic sporting two-hander.
McEnroe’s comments came two days before Djokovic was forced to withdraw from his semi-final clash with Alexander Zverev due to a muscle problem.
Novak Djokovic and Andy Murray haven't decided whether to continue their player-coach partnership.