Top performer brings deserters back (4)
I believe the answer is:
star
'top performer' is the definition.
(I've seen this before)
'deserters back' is the wordplay.
'deserters' becomes 'rats' (I've seen this in another clue).
'back' shows that the letters should be reversed in order.
'rats' backwards is 'STAR'.
'brings' acts as a link.
(Other definitions for star that I've seen before include "Take the lead role" , "Public figure" , "Symbol of excellence" , "Heavenly apparition" , "Celebrated performer" .)