Nearly 32 y/o Djoko has just won his third Slam in succession and he is gunning for his second NCYGS. Your point!?
Also the nearly 33 y/o Fed was playing the 5 set in the 2014 W only because of the Djoko's mental brainfart while leading 5:2 deep in the fourth. Nothing strange about 2014 Djokovic to have some mental demons at that time since he was coming of 3 tough loses in Slam finals in a raw and 2 tight 5 set loses against Wawrinka (2014 AO) and Rafa (2013 RG).