Make light of not working after performance (4,4)
I believe the answer is:
play down
'make light of' is the definition.
(to play something down is to reduce its importance)
'not working after performance' is the wordplay.
'not working' becomes 'down' (I've seen this in another clue).
'after' is a charade indicator (letters next to each other).
'performance' becomes 'play' (performance in a theatre).
'down' after 'play' is 'PLAY DOWN'.
(Other definitions for play down that I've seen before include "Give little importance to" , "Seek to lessen the importance (of something)" , "Gloss over" , "what Antrim team may do?" , "Make light of" .)