A bird fight - the racket! (7)
I believe the answer is:
sparrow
'a bird' is the definition.
(sparrow is a kind of bird)
'fight the racket' is the wordplay.
'fight' becomes 'spar' (sparring is a kind of fighting).
'the racket' becomes 'row' (both can mean a noisy disturbance).
'spar'+'row'='SPARROW'
(Other definitions for sparrow that I've seen before include "Small brown bird" , "Little brown bird" , "Passerine bird" , "bird produced" , "(Formerly very) common British bird" .)