Successful record beaten after defeat (5,3)
I believe the answer is:
smash hit
'successful record' is the definition.
'beaten after defeat' is the wordplay.
'beaten' becomes 'hit'.
'after' is a charade indicator (letters next to each other).
'defeat' becomes 'smash' (I've seen this before**).
'hit' put after 'smash' is 'SMASH-HIT'.
(Other definitions for smash hit that I've seen before include "great entertainment" , "roaring success" , "most popular show!" , "number one" , "Great success" .)