Master performing reliably in the opening movement? (8,3)
I believe the answer is:
skeleton key
'master' is the definition.
(I know that skeleton key is a type of master)
'performing reliably in the opening movement?' is the wordplay.
I cannot quite see how this works, but
'performing' could be 'on' (as in being on stage) and 'on' is located in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
This explanation may well be incorrect...
(Other definitions for skeleton key that I've seen before include "help needed identifying bones perhaps" , "That which can open numerous doors" , "Versatile opener" , "It can open several locks" , "Opener of many locks" .)