one poster somewhere said that maybe djokovic was play8ing just a ''player piano" (a piano that can play by itself ) - and because they found on key was depressed down while his arms were away from the piano -- but it's possible the key (in a rented apartment in paris) was just a sticky one..even as a pianist i can't tell --
but it appears nole really is =playing - in a very beginner way...and certainly makes the normal hesitations i know every beginner would ...especailly if playing by ear as he does..