Not allowed the same beat (5)
I believe the answer is:
outdo
'beat' is the definition.
(outdoing is a kind of beating)
'not allowed the same' is the wordplay.
'not allowed' becomes 'out' (I've seen this before).
'the same' becomes 'do' (abbreviation for ditto).
'out'+'do'='OUTDO'
(Other definitions for outdo that I've seen before include "Best" , "Eclipse" , "going to top?" , "Exceed" , "Perform better than surpass" .)