Revolutionary piece, oddly ignored during subsequent musical performance (7)
I believe the answer is:
recital
'musical performance' is the definition.
(I've seen this before)
'revolutionary piece oddly ignored during subsequent' is the wordplay.
'revolutionary' says the letters should be written in reverse.
'oddly ignored' means one should take alternating letters.
'during' indicates putting letters inside.
'subsequent' becomes 'later' (similar in meaning).
The alternate letters of 'piece' are 'ic'.
'ic' going within 'later' is 'laticer'.
'laticer' reversed gives 'RECITAL'.
(Other definitions for recital that I've seen before include "gig" , "Public performance of music" , "Article found in performance" , "One's performance" , "(Usually solo) concert" .)